Owner`s Manual
WOOD PELLET FURNACE
OWNER’S MANUAL
M255 P; M255 PE
Tested &
Listed By
US
Portland
Oregon USA
OMNI-Test Laboratories, Inc.
117-O-24-2
Save This Manual
For Future Reference
(p/n 9000311 - REV. A) - 15-MAY-2015
by Central Boiler, Inc.
20502 160th Street • Greenbush, MN 56726
CentralBoiler.com • MaximHeat.com
The Maxim Wood Pellet Furnace is listed by OMNI-Test Laboratories to the following standards: CAN/CSA B366.1-M91-2007 Solid
Fuel-Fired Central Heating Appliances, UL 391-2006 Solid Fuel and Combination Fuel Central and Supplementary Furnaces.
French Owner's Manual and decal set available upon request from your dealer.
(Manuel d'installation en français et décalcomanies disponible sur demande auprès de votre revendeur)
Manuel d'installation en français : p/n 9000269 Décalcomanies : p/n 9409
The Maxim Wood Pellet Furnace includes two 4-foot chimney sections (6" ASHT) listed to UL 103.
Maxim M255 P / M255 PE thermal output rating: 165,215 Btu/hr (47.5 kW) - maximum
Thermal Output Rating*:
Manufacturer's Rated Heat Output Capacity: 180,000 Btu/hr
Annual Efficiency Rating*: 89% (lower heating value), 82% (higher heating value)
*Performance is a product of the combustion rate, combustion efficiency and heat exchange efficiency with a single fuel load without refueling.
Results vary based on wood species, wood quality, wood quantity and moisture content. Efficiencies are determined under the same test conditions
using higher heating value, lower heating value and annual fuel utilization efficiency (AFUE).
• This heater is certified to comply with the 2015 U.S. Environmental Protection Agency's particulate emission standards for
wood heaters sold after May 15, 2015. Under specific test conditions this heater has been shown to deliver heat at rates
ranging from 0 to 165,215 Btu/hr.
• This wood heater has a manufacturer-set minimum low burn rate that must not be altered. This wood heater needs periodic
inspection and repair for proper operation. It is against federal regulations to operate this wood heater in a manner inconsistent
with operating instructions in this manual.
• DO NOT OVERFIRE THIS HEATER. Attempts to achieve heat output rates that exceed heater design specifications can result
in permanent damage to the heater.
• This model is qualified for year-round use.
• Any person(s) operating a hydronic heater must comply with all applicable laws, including but not limited to local ordinances.
• Improper use or failure to maintain the hydronic heater may cause nuisance conditions. The person(s) operating a hydronic
heater is/are responsible for operation in a manner that does not create a public or private nuisance condition. Check State
and local regulations for stack height requirements, setback distances and for the time of the year the appliance may be
operated before installation. Meeting the distance and stack height recommendations from the manufacturer and requirements
in applicable State and local regulations may not always be adequate to prevent nuisance conditions in some areas due to
terrain or other factors.
• This outdoor furnace should not be installed in a building that could be damaged or where a financial loss could occur from
smoke, soot or water.
Vermont certification is with wood pellets as a fuel source ONLY.
INSTALLATIONS IN MASSACHUSETTS:
1. All installation components must be products approved in the Commonwealth of Massachusetts by the
Gas and Plumbing Board.
2. The minimum run of tubing from the water heater to a fan coil is 50 linear feet.
3. Persons operating this hydronic heater are responsible for operation of the hydronic heater so as not to
cause a condition of air pollution as defined in 310 CMR 7.01(1).
For parts and accessories, service or repairs, call your authorized Central Boiler dealer or heating
contractor. Record the information below for future reference.
Model
Dealership Name
Owner Name
Serial Number
Installation Date
Phone Number
Table of Contents
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
SECTION 1 – GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Specifications and Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Removing from Pallet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Shipping Slot Covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Potable Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Antifreeze . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Corrosion Inhibitor Plus™ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Shut-Off Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
SECTION 2 – LOCATION AND FOUNDATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Selecting a Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Foundation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Leveling the Outdoor Furnace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Clearances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
SECTION 3 – ELECTRICAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Ground Rod . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
SECTION 4 – GAS SUPPLY CONNECTION (P MODELS) AND IGNITOR OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Gas Supply Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
How to Operate the Gas Ignitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Ignition Sequence - P Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Ignition Sequence - PE Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
SECTION 5 – CHIMNEY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Chimney Height . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Chimney Draft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
SECTION 6 – SYSTEM INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
SUPPLY AND RETURN LINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Above Ground or Winter Installations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Digging the Trench . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Underground Electric Wire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Connecting to Existing Heating System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Backfilling Water Line Enclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
CIRCULATION PUMPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Water Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Access to Ports on Furnace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Installing Circulation Pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Shut-Off Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Thermostatic Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
MAXIM THERMOSTATIC VALVE - HOW IT WORKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Purging Air from the System - Manual Air Bleeders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
WATER HEATER INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
EXISTING FORCED AIR INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Thermostatic Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
HEATING MULTIPLE ZONES OR BUILDINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
HYDRONIC INSTALLATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Pressurized Water System Installations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Water-to-Water Heat Transfer System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Vented System Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Direct Circulation Baseboard Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Radiant Floor System Installations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Pool and/or Hot Tub Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
SECTION 7 – FILLING SYSTEM WITH WATER AND PURGING AIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
FILLING OUTDOOR FURNACE WITH WATER AND PURGING AIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
SECTION 8 – OPERATING INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Fuel Quality and Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
FireStar Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Operating Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Filling the Hopper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Smoke in Hopper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
SECTION 9 – ROUTINE MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
ROUTINE MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
9.1 Water Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
9.2 Ash Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
9.3 Firebox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
9.4 Gaskets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
9.5 Heat Exchangers and Chimney Transition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
9.6 Aerator and Burn Chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
9.7 Door and Hopper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
9.8 Check Fuel Door Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
9.9 Thermal Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
9.10 Test Thermal Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
9.11 Gas Ignitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
WATER QUALITY AND MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
POST HEATING SEASON MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
SECTION 10 – TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
SECTION 11 – DECALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
SECTION 12 – WIRING DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
SECTION 13 – PARTS LISTINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
INTRODUCTION
Labeling and Terminology
The outdoor furnace and this owner's manual use the
following terms and symbols to bring attention to the
presence of hazards of various risk levels and important
information concerning the use and maintenance of the
furnace.
DANGER: Indicates an imminently hazardous situation
which, if not avoided, will result in death or serious
injury.
WARNING: Indicates presence of a hazard which
can cause severe personal injury, death, or substantial
property damage if ignored.
CAUTION: Indicates presence of a hazard which will
or can cause minor personal injury or property damage
if ignored.
NOTE: Indicates supplementary information worthy
of particular attention relating to installation, operation,
or maintenance of the furnace but is not related to a
hazardous condition.
Be sure to follow all instructions and related precautions
as they are meant for your safety and protection. Store
this manual in a readily accessible location for future
reference.
Foreword
This manual is to be used as a guideline for the
installation, operation and maintenance of the Maxim
Wood Pellet Furnace. This manual is organized into
thirteen sections for easy reference.
Section 1 – General Information;
Section 2 – Location and Foundation;
Section 3 – Electrical;
Section 4 – Gas Supply Connection and
Ignitor Operation;
Section 5 – Chimney;
Section 6 – System Installation;
Section 7 – Filling System with Water and
Purging Air;
Section 8 – Operating Instructions;
Section 9 – Routine Maintenance;
Section 10 – Troubleshooting;
Section 11 – Decals;
Section 12 – Wiring Diagram;
Section 13 – Parts Listing.
Anyone owning or operating this outdoor furnace must
read, fully understand, and follow all of the information
in this manual.
NOTE: In higher populated areas, extend
the chimney to a height above the roofs of
surrounding buildings (see Chimney Height in
the Chimney section).
NOTE: The outdoor furnace may be connected
to an existing boiler system or hot water heating
system by a qualified installer only. However, the
outdoor furnace must not be pressurized.
4
IMPORTANT PRECAUTIONARY INFORMATION
The information contained on this page appears throughout this manual. Be sure to read carefully and
understand these precautions before, during and after the installation, operation and maintenance
of the furnace.
WARNING
This outdoor furnace is not intended to be the
only source of heat. In the event of a prolonged
power failure, a generator may be used to prevent
lines from freezing. Should the system be left
unattended, run out of fuel or require service,
an alternate heating source in the building being
heated should be in place to prevent damage
caused by freezing.
WARNING
This outdoor furnace is not intended or certified
to be installed inside habitable space. Do not
install the outdoor furnace inside your home.
CAUTION
This outdoor furnace should not be installed in
a building that could be damaged or where a
financial loss could occur from smoke, soot or
water.
WARNING
This outdoor furnace and/or chimney must not
be installed inside or under any configuration or
construction that contains combustible materials
as part of the structure or configuration. The
chimney is not intended or safety tested to
be used or installed other than on the furnace
located outside of any structure or enclosure.
WARNING
Maintain the following clearances from
combustibles for the outdoor furnace
installation:
• 8" (20 cm) from the transition box
• 6" (15 cm) from the sides
• 48" (122 cm) from the front
• 8" (20 cm) from the chimney
• 27" (68.5 cm) from the top
• The foundation must be noncombustible
WARNING
Use only chimneys listed to UL 103 HT for
installation. The chimney and flue pipe must be
clean and in good condition.
WARNING
Be sure the outdoor furnace is filled with water
before firing. Water level is safe when the water
level indicator rod is above the vent cap (Fig. 1).
Corrosion Inhibitor Plus™ must be added before
the initial fill (see Water Quality and Maintenance).
Fig. 1
WARNING
Installation of the outdoor furnace is to be
performed by a qualified installer.
WARNING
WARNING
When installing a heat exchanger on an existing
hot water boiler, be sure none of the existing
system safety controls are disabled.
Do not allow combustible materials (straw, hay
or wood) near the outdoor furnace. Keep the
perimeter of the outdoor furnace clear and clean.
WARNING
WARNING
If this appliance is installed inside a building and
the LP tank capacity exceeds one pound, the tank
and regulator must be located outside.
Never leave the firebox door or hopper lid open
or ajar when unattended.
5
IMPORTANT PRECAUTIONARY INFORMATION
The information contained on this page appears throughout this manual. Be sure to read carefully and
understand these precautions before, during and after the installation, operation and maintenance
of the furnace.
WARNING
Use only those listed fuels recommended by
the manufacturer of your unit. Never use the
following: trash, plastics, gasoline, rubber,
naptha, household garbage, material treated
with petroleum products (particle board, railroad
ties and pressure treated wood), leaves, paper
products, and cardboard.
WARNING
Burn premium quality wood pellets only.
WARNING
This heater is designed to burn premium quality
wood pellets only. Higher efficiencies and
lower emissions generally result when burning
premium quality wood pellets, as compared to
standard pellets. DO NOT BURN: unseasoned
wood, garbage, tires, lawn clippings, leaves,
brush trimmings or general yard waste, materials
containing asbestos, materials containing lead,
mercury or other heavy toxic metals, materials
containing plastic, materials containing rubber,
waste petroleum products, paints and paint
thinners, asphalt products, chemicals, coal,
glossy or colored paper, construction and
demolition debris, plywood, particleboard, salt
water driftwood and other previously salt water
saturated materials, manure, animal carcasses
and asphalt products. Burning these materials
may result in release of toxic fumes or render the
heater ineffective and cause smoke.
WARNING
The outdoor furnace vent cap must fit loosely
on the vent opening. Do not force the cap down
or try to seal it tightly onto the vent pipe. Do
not extend or restrict the vent pipe or opening.
DO NOT ALLOW THE OUTDOOR FURNACE TO
PRESSURIZE.
WARNING
Disconnect the electrical power to the furnace
and remove all ash from the firebox before
performing maintenance that requires draining
the water or replacing an electrical component.
WARNING
Allow the outdoor furnace to thoroughly cool
before draining water from the outdoor furnace.
Never drain water from the outdoor furnace with
live ash or fire in the firebox. If the water in the
outdoor furnace ever boils, be sure to check the
water level and restore to full. If water is added,
the proper level of Corrosion Inhibitor Plus™ (p/n
1650) must be maintained.
WARNING
When cleaning the outdoor furnace, be careful
not to spill any hot ash.
CAUTION
Never use gasoline, gasoline-type lantern fuel,
kerosene, charcoal lighter fluid, or similar liquids
to start or ‘freshen up’ a fire in this outdoor
furnace. Keep all such liquids well away from the
outdoor furnace while it is in use.
CAUTION
Always wear the appropriate personal protective
gear when cleaning ash from the firebox.
WARNING
Sulfuric acid in the test kit is a corrosive acid.
Handle carefully. Carefully read and follow
precautions on test chemical labels. Keep test
chemicals away from children. Safely dispose of
tested samples.
NOTE: All installations and operations must be
in accordance with local and state codes which
may differ from the information in this manual.
NOTE: Check with your insurance company to
see if they have any location requirements.
NOTE: Any changes to an existing boiler should
be done by a qualified installer in accordance
with applicable codes.
NOTE: Do not connect this outdoor furnace to a
chimney flue serving another appliance.
NOTE: Chloride or sulfurous gases can be
generated if plastic or rubber is burned and will
mix with the moisture from the wood pellets and
form hydrochloric or sulfuric acids in the firebox,
creating corrosion.
NOTE: If installed in a non-habitable building,
adequate combustion air and ventilation must be
provided.
6
SECTION 1 – GENERAL INFORMATION
Anyone owning or operating this outdoor furnace must
read, fully understand, and follow all of the information
in this manual.
Specifications and Dimensions
Fig. 2
Removing from Pallet
The outdoor furnace is secured to the shipping pallet
with four brackets. To remove these brackets, loosen
(but do not remove) the two screws securing each
shipping slot cover and slide the cover up. Remove the
bolts securing the bracket to the pallet and remove the
bracket.
NOTE: Lift the outdoor furnace only where
specified by Fig. 3.
Fig. 3
G
D
OPTION #2
Use forklift, chain
and hook here.
E
TM
R
E STA
Boiler
FIR
by
Central
5%
Output
Heat
60%
Temp
Water
LOW
TM
100%
STAR
Boiler
MEDIUM
by
FIRE
HIGH
1%
20%
Air
5%
Output
Heat
60%
Temp
Water
to
Hold
Prime
to
Press
Out
Twice
Clean Clean
Mode
LOW
100%
MEDIUM
HIGH
p/n
9507
1%
Hold
Light
to
20%
Press
Twice
Auto
for
Relight
Central
Auger
Adjust
65%
Ignition
Air
Ignition
Auger
Adjust
65%
Power
to
Hold
Prime
to
Press
Out
Twice
Clean Clean
Mode
p
Hold
Light
to
Press
Relight
Auto
Enabled
Twice
Auto
for
Relight
Power
Relight
Auto
Enabled
No
Forks
B
No
Forks
F
30
"
30
"
OPTION #1
Place forklift tines
under furnace within
areas shown.
C
H
A
Maxim M255 P; M255 PE Measurements
A
B
C
D
E
F
G
H
in.
34
57
49.5
36
48
59.5*
117.5**
14.5
cm
86
145 126 91,5 122
151*
298,5**
37
* Measurement (F) is from firebox door to chimney
inspection cover.
** Measurement (G) with two 4-foot chimney sections.
Shipping Slot Covers
Position each shipping slot cover so it is flush with the
bottom of the outdoor furnace; then secure the cover by
tightening the two screws. Make sure all four covers are
properly positioned and secured (Fig. 4).
Fig. 4
© 2014 Central Boiler
NOTE: See Section 5 for chimney installation
guidelines.
NOTE: The Maxim Furnace includes two 4-foot
(1.2-meter) ASHT 6" in diameter chimney sections
listed to UL103HT. For chimney sections or
chimney replacement, use only genuine Central
Boiler chimney components. Parts are available
from an authorized Central Boiler dealer.
Section 1 - General Information
7
Options for Increasing Fuel Storage
An optional 48-Bushel Hopper is available (p/n 9660
or 9760) for increasing fuel storage. This hopper can
be positioned to the side of the furnace using a 5-1/2'
Auxiliary Auger Kit (p/n 9440).
NOTE: Do not use automotive or RV types of
antifreeze.
A 6' Auxiliary Auger Kit (p/n 6453) and an 8' Auxiliary
Auger Kit (p/n 9454) are also available for other
applications. The auxiliary augers can also be used with
larger external bins.
Corrosion Inhibitor Plus™
To aid in protecting the system from corrosion, it is
imperative to add Central Boiler Corrosion Inhibitor
Plus™ (p/n 1650). When initially filling the system (see
Finalizing the Installation), add the Corrosion Inhibitor
Plus™ before adding water to the system. Any time
water is added to the system, Corrosion Inhibitor Plus™
must be added if a tested water sample indicates it is
necessary (see Water Quality and Maintenance).
An optional Auxiliary Auger Vibrator with Timer
Kit (p/n 9458) can be installed on the auxiliary auger
connected to an external hopper. Vibration occurs based
on a timer setting.
Potable Water
If the outdoor furnace is to heat potable water associated
with commercial food preparation or for heating milkhouse hot water, it is recommended to install a doublewall heat exchanger. Also, when filling the system with
water, a backflow preventer must be installed in the line
used for filling.
Antifreeze
Most outdoor furnaces are installed without antifreeze
when an existing heating system is in place and there
is no anticipation of leaving the outdoor furnace
unattended for extended periods of time. If the building
being heated has an alternate heat source, system water
may be kept from freezing by running the circulating
pump(s) and drawing heat from the existing heat
emitter(s).
To prevent freezing if the outdoor furnace is not fired for
extended time periods or if lengthy power outages are
anticipated during cold weather, a nontoxic propylene
glycol boiler-type may be used in the system. Some
types of antifreeze that contain various inhibitors
have been known to create problems like coagulation
and jelling. To prevent potential problems, do not
use propylene glycol that is premixed with unknown
inhibitors. Central Boiler Corrosion Inhibitor Plus (p/n
1650) is compatible with straight propylene glycol. It is
important to use Corrosion Inhibitor Plus with straight
propylene glycol for corrosion protection.
NOTE: If using antifreeze, use Test Kit (p/n 597)
when testing the treated water in the outdoor
furnace (see Water Quality and Maintenance).
Corrosion Inhibitor Plus™ is composed of common
materials and is biodegradable. However, in keeping
with good safety and environmental practices, the
supplier recommends the following if draining treated
system water becomes necessary:
• You may drain the outdoor furnace to a home septic
system. Central Boiler Corrosion Inhibitor Plus™
is biodegradable and can be properly treated in a
residential septic system. If doing so, however, be
careful not to overflow the septic system.
• Do not drain the outdoor furnace in such a manner
that the drain water could in any way contact
surface water, stream, river, estuary (where a river
meets a sea), lake, pond, ocean or other types of
waters.
• Do not drain to any location within 50 feet (15
meters) of any water well.
Shut-Off Valves
Shut-off valves must be installed on each hot supply
and return water line so each line can be shut off
individually for purging air from the system. Be sure all
valves and fittings are metal. Do not use plastic valves
or fittings.
If adding antifreeze to the system, it is imperative
that the entire system contain at least 30% antifreeze
concentration mixed with softened water to prevent
bacterial growth and minimize minerals in the system.
Bacterial growth is likely to occur with low antifreeze
concentrations and can cause corrosion in the furnace
water jacket and/or clogging of heat exchangers. To
confirm the antifreeze solution is adequate, allow the
pumps to circulate for at least 24 hours and then obtain
a sample of the system water. Using an antifreeze tester,
the solution must be protected to 0˚F (-18˚C) or below.
NOTE: Be sure to adhere to all warnings and
precautions on the antifreeze label.
8
Section 1 - General Information
SECTION 2 – LOCATION AND FOUNDATION
Selecting a Location
To ensure the Maxim Furnace functions as designed,
careful planning and proper installation are imperative.
Be sure to read carefully and observe all of the
information in the entire owner's manual.
If any installation questions arise that cannot be
answered by the information in this manual, be sure to
contact your dealer.
• This outdoor furnace is not intended or certified to
be installed inside habitable space. Do not install
the outdoor furnace inside your home.
• This outdoor furnace may be installed outdoors or
in non-habitable structures and must be installed
in accordance with all applicable codes and
regulations.
• Check with your insurance company to see if they
have any location requirements.
❑❑ If the ground at the location is unstable or subject
to frost heaving, consider installing 2" closed-cell
insulation under the front portion of the concrete
slab the outdoor furnace will be installed on, and
under the area around the slab used for walking
(see Fig. 6).
❑❑ Carefully consider the location of, and the distance
to, the LP tank if one is to be used (see Gas Supply
Connection and Ignitor Operation section).
Foundation
The outdoor furnace may be installed directly on stable,
level ground without the necessity of a foundation.
If the ground is unstable, one option is to use patio
blocks, bricks or pavers under the base as indicated in
Fig. 5. Another option is to pour a concrete foundation.
Fig. 5
• This outdoor furnace should not be installed in a
building that could be damaged or where a financial
loss could occur from smoke, soot or water.
When selecting a suitable location, carefully consider
each of the following:
❑❑ Must be installed in accordance with all applicable
codes and regulations.
❑❑ A qualified installer must perform the installation
of this supplementary outdoor furnace and must
determine how to install it to be compatible with
the existing heating source.
❑❑ Consider prevailing winds and the direction
exhaust from the chimney will travel.
❑❑ The shorter the distance between the outdoor
furnace and building(s) being heated, the lower the
cost will be for the installation of the hot supply
and return water lines and insulation.
❑❑ Be sure to maintain the required clearances to
combustibles and recommended maintenance
clearances.
❑❑ ThermoPEX pre-insulated piping is recommended
for all underground installations. Other types of
piping should not be buried in low-lying areas with
standing water or with a very high water table,
or under an area of heavy vehicle traffic unless
protected from excessive compression.
Section 2 - Location and Foundation
9
Fig. 6
Maxim Foundation Dimensions
Optional 48-Bushel
Hopper with Foundation
Optional Foundation
48"
12"
87"
51"
12"
37"
12"
2-1/2" Optional
14"
51"
14"
52"
48-Bushel
Fuel Hopper
Furnace
14"
2"
5-1/2-Foot
Transfer
Auger
Optional
Cement
Loading Area
Maxim
14"
Maxim
52"
Furnace
Base
12"
Front
12"
48"
12"
18"
72"
Shown without optional hopper.
13"
12"
Recommended
maintenance clearances
2" rigid foam insulation
(optional)
Foundations dimensions are 1-1/2
in. beyond the outside perimeter
of the base.
Front
37"
12"
18"
72"
CAUTION
Do not use any combustible
materials for the foundation.
Outdoor furnace must be installed on a noncombustible surface or
foundation that incorporates an enclosure that will prevent supply
and return lines from possible exposure to sunlight, fire, or
physical damage that may be caused by an occurrence outside
the outdoor furnace enclosure. Foundation may consist of
concrete, crushed rock, or patio blocks.
© 2014 Central Boiler
To install the outdoor furnace on a concrete foundation,
refer to Fig. 6 for dimensions and for the location of
the hollowed-out area. A 4" to 6" (10 cm to 15 cm)
thick concrete slab works well; however, a thicker slab
may be used to obtain the desired firebox door opening
height.
If installing on an existing slab, it may be necessary
to use patio blocks, bricks or pavers (Fig. 5) to allow
access to the water lines.
NOTE: In all installations, the outdoor furnace
must not be operated with the back panels
removed. Make necessary allowances for access
to the back of the outdoor furnace.
If the area for the concrete slab is unstable or subject
to frost heaving, consider installing 2" closed-cell
insulation under the front portion of the concrete slab
the outdoor furnace will be installed on, and under the
area around the slab used for walking (see Fig. 6).
NOTE: The installation surface or foundation
must be noncombustible. The hot supply and
return lines must also be protected from possible
exposure to sunlight, fire or physical damage.
Foundations may consist of concrete, crushed
rock or patio blocks.
10
Leveling the Outdoor Furnace
CAUTION
The back of the outdoor furnace must not be
lower than the front of the outdoor furnace.
The Maxim should be leveled so that the back of the
transition box (i.e., the burner auger motor end) is
slightly higher than the front. Smoke can condense
into creosote inside the burner auger tube. If the burner
auger is not sloped down toward the front of the furnace,
condensation can form in the burner auger tube and drip
into the transition box.
WARNING
Disconnect the electrical power at the main
power source and turn off the gas supply at the
appliance service valve.
1. Disconnect the electrical power at the main power
source and turn off the gas supply at the appliance
service valve.
2. Remove the access panels from the back corner of
the furnace and set aside.
Section 2 - Location and Foundation
3. Place a level on the back of the burner auger motor
as shown in Fig. 7. The back of the transition box
should be slightly higher than the front, indicated
when the level is vertical and there is a small gap
(from 1/16" to 3/32", or 1.6 mm to 2.4 mm) between
the level and the top of the burner auger motor and
no gap between the level and the bottom of the
burner auger motor.
Clearances
NOTE: Clearance to combustibles from the
chimney transition box is 8" (20 cm); HOWEVER,
if installing with the back of the outdoor furnace
facing an immovable wall, object, etc., you
must maintain 36" (91.5 cm) of clearance to the
wall, object, etc. in order to perform periodic
maintenance (see Fig. 8).
Fig. 8
Fig. 7
Maxim Leveling Procedure
Small Gap
(No less
than 1/16")
Place Decal
Here
Centered
No Gap
NOTE
Use shims to position
feed assembly as shown.
WARNING
Shims
Foundation
Foundation
Shim
(Shown in black)
Maintain the following clearances from
combustibles for the outdoor furnace
installation:
• 8" (20 cm) from the transition box
• 6" (15 cm) from the sides
• 48" (122 cm) from the front
• 8" (20 cm) from the chimney
• 27" (68.5 cm) from the top
• The foundation must be noncombustible
Foundation
© 2014 Central Boiler
4. Use shims as necessary under the outdoor furnace
in the locations shown until the procedure in Step
3 indicates that the back of the transition box is
slightly higher than the front.
NOTE: Periodically check that the outdoor furnace
is leveled as described in these instructions
because frost can cause the foundation to move.
5. Install the access panels on the back corner of the
furnace.
6. Connect the electrical power at the main power
source and turn on the gas supply at the appliance
service valve.
7. Connect the electrical power at the main power
source and turn on the gas supply at the appliance
service valve.
Section 2 - Location and Foundation
11
SECTION 3 – ELECTRICAL
NOTE: Any electrical installation should be
done by a qualified installer in accordance with
applicable codes.
Fig. 9
Ground Rod
The outdoor furnace must be electrically bonded to
ground in accordance with the requirements of the
authority having jurisdiction or, in absence of such
requirements, with the National Electrical Code, ANSI/
NFPA 70 and/or the Canadian Electrical Code Part 1,
CSA C22.1 Electrical Code.
Install the ground rod and connect it to the outdoor
furnace.
1. In the water line trench near the outdoor furnace,
drive the ground rod into the ground until the top of
the ground rod is below the ground surface.
2. Remove the side and back panels; then route the
ground wire from the ground rod under the outdoor
furnace base and over to the bottom left corner at the
back of the outdoor furnace.
3. Secure the ground terminal with the self-drilling
screw provided. Secure the ground wire to the
terminal; then secure the ground wire to the ground
rod with the clamp. Tighten all hardware securely.
12
Section 3 - Electrical
SECTION 4 – GAS SUPPLY CONNECTION (P Models) AND
IGNITOR OPERATION
Gas Supply Connection
The M255 P is designed so that a one-pound propane
cylinder may be connected to the gas ignitor. Thread
the cylinder on to the regulator installed on the gas
valve (Fig. 11). This configuration works well for all
temperatures.
Temperatures below 0˚F (-18˚C) also will cause small
LP gas regulators to work incorrectly, outputting gas
pressures that are too high or too low. A two-regulator
system using a first-stage and a second-stage regulator,
or a combination two-stage regulator (p/n 1930) such as
the one shown in Fig. 13 should be used.
Fig. 11
Fig. 13
CAUTION
Other sizes of portable propane cylinders may be
connected to the regulator with the proper hose and
fittings.
Because liquid propane (LP) evaporates and turns to
gas at a slower rate when the temperature of the tank
is lower, sustained temperatures below 0˚F (-18˚C) will
lead to reduced gas pressure in small LP tanks. This
will lead to a drop in burner manifold pressure while
the burner is operating. If sustained temperatures below
0˚F (-18˚C) are expected, a properly installed tank of
at least 100-lb capacity must be installed (see Fig. 12).
Fig. 12
Make sure all covers for the gas ignition system
on the appliance are in place during operation
and service.
WARNING
Once the gas supply is connected, the appliance
and gas connection must be tested for leaks
before placing the appliance in operation.
For temperatures below 0˚F (-18˚C), use either the
configuration in Fig. 11 or the one in Fig. 13 with a
2-stage regulator system and a larger tank.
How to Operate the Gas Ignitor
The outdoor furnace utilizes a gas burner to ignite the
fuel in the burn chamber. The FireStar controller can
also be set to automatically relight the fuel if needed.
NOTE: For more detailed information, refer to
the FireStar Controller Operating Instructions
section.
There are two ways to start the gas burner:
1. Press and hold the Ignition button on the FireStar
controller until the LED display indicates
and
the burner fan operates.
NOTE: The gas burner will start regardless of the
temperature of the burn chamber; however, if the
temperature of the burn chamber is greater than
350˚F (177˚C), the gas burner will immediately
shut off.
2. If Auto Relight is enabled and the controller is in
NORMAL or MEDIUM mode, the ignition process
will start if the burn chamber temperature falls below
300˚F (149˚C).
Section 4 - Gas Supply Connection and Ignitor Operation
13
Ignition Sequence - P Models
The ignition sequence is a series of steps that
automatically occur to ensure the gas ignitor starts
properly before the system begins to operate. During
ignition, the following will take place:
1. The burner fan will operate to provide air flow for
combustion.
2. Once the pressure switch senses air flow, it will
energize the gas ignition module.
3. The gas ignition module turns on the gas valve and
spark electrode, igniting the gas burner to light the
wood pellets in the burn chamber.
4. The feed and burner augers run for 60 seconds,
delivering fuel to the burn chamber.
5. The gas burner will continue to burn until the burn
chamber reaches a high enough temperature to
sustain burning the wood pellets, or for 10 minutes,
at which time the controller will turn off the gas
burner.
14
Ignition Sequence - PE Models
The ignition sequence follows a control logic to ensure
safe and effective ignition. The ignition sequence is as
follow:
1. The water temperature must be low enough for the
furnace to shift into demand mode.
2. The fan will start and operate at the ignition fan
speed and the Firestar control will send voltage to
the igniter relay.
3. The air proving switch will close, completing the
ignition relay control circuit.
4. The electric ignitor will warm up and heat the air
blowing across it into the burn chamber.
5. The auger will cycle periodically to feed the required
amount of fuel into the burn chamber, and to agitate
any pellets already present in the burn chamber.
6. The ignitor will operate until the burn chamber
reaches a temperature that is high enough to sustain
itself, or for ten minutes, at which time the ignitor
will turn off.
Section 4 - Gas Supply Connection and Ignitor Operation
SECTION 5 – CHIMNEY
Chimney Height
The minimum recommended chimney length is eight
feet (2.4 m). Two 4-foot (1.2 m) sections are standard.
Additional sections may be needed (see Chimney Draft
section).
In higher populated areas, extend the chimney to a
height above the roofs of surrounding buildings. Use
Central Boiler Chimney Extensions when extending
the chimney. When only the standard eight feet (2.4 m)
of chimney are used, the sections must be secured at
the connection joint with four screws to stabilize the
extension.
Be considerate of neighbors when operating your
outdoor furnace. If you use your outdoor furnace in the
summer months, be certain your chimney exhaust is not
adversely affecting neighbors with open windows.
If located within 300 feet (91 m) of any residence not
served by the outdoor furnace, it is recommended that
the chimney be at least 2 feet (0.6 m) higher than the
peak of the residence served.
Fig. 14
NOTE: If more than three 4-foot (1.2 m) sections
of chimney are used, a support (e.g., a pole, pipe
or other structural support) may be installed
from the ground that can withstand wind. Other
reinforcement recommendations are shown in
Fig. 15.
If extensions are added to the standard eight feet (2.4 m) of
chimney, the chimney should be reinforced appropriately.
Fig. 15 shows chimney support recommendations when
three or more sections are used. When adding sections of
chimney, make sure that there is nothing within the fall
zone of the chimney that could be damaged. If something
is located within the fall zone and cannot be removed,
guy wires or braces may need to be installed to prevent a
falling chimney from causing damage (see Fig. 15).
NOTE: For chimney extensions or chimney
replacement, use only genuine Central Boiler
chimney components. Parts are available from
an authorized Central Boiler dealer.
The installation of a spark arrester is recommended,
particularly where there are dry conditions or where
there is combustible material near the unit, unless the
installation of a spark arrester is prohibited by local
requirements. Use common sense to avoid potential
fires, including exercising caution when disposing of
ash, cleaning and refueling. Keep all highly combustible
materials (e.g., gasoline, propane, leaves, pine needles,
etc.) away from an operating unit at all times. Take
special precautions in windy conditions.
Fig. 15
Section 5 - Chimney
15
4. Objects like buildings and trees in close proximity or
Chimney Draft
nearby terrain (e.g., hills, valleys, etc.) can adversely
Proper draft is necessary for the Maxim to operate
affect air flow in the chimney (see Fig. 16). Adding
optimally. Draft occurs when the temperature in the
chimney sections may overcome these factors.
chimney is high enough and/or the chimney is high
enough to cause a negative pressure that "pulls" the
exhaust up and out the chimney. The higher the burn Fig. 16
rate and fan settings, the more sections of chimney that
will be required to provide proper draft.
NOTE: Adding more chimney sections increases
the amount of negative pressure in the chimney.
NOTE: A qualified installer may perform the
following test to check for proper draft.
1. Drill a hole in the chimney inspection cover; then
with the outdoor furnace and chimney at normal
operating temperature, use a manometer to check
draft. Flue draft should be between -0.02 in. WC (-5
Pa) and -0.05 in. WC (-12.45 Pa). If the flue draft is
lower, add more chimney sections.
2. After the test, fill the hole in the chimney inspection
cover with high-temp silicone.
3. If a spark arrestor is being used, make sure it is clean
and unobstructed.
16
Section 5 - Chimney
SECTION 6 – SYSTEM INSTALLATION
SUPPLY AND RETURN LINES
Determine the configuration of the supply and return
lines from the outdoor furnace to where the supply and
return lines will connect to the existing heating system.
Central Boiler recommends using the ThermoPEX®
piping system.
Fig. 17
ThermoPEX is a fully assembled, pre-insulated
piping system consisting of two 1" Central PEX lines
or two 1-1/4" PEX lines. The two lines (one a supply
and one a return line) are insulated with high-density
urethane insulation and a thick, durable, waterproof,
polyethylene outer jacket. One of the lines is marked
with a black stripe for identification.
NOTE: To prevent ground water from entering the
house, do not use drain tile, PVC pipe with bubble
wrap, or any other inferior material for insulating
the water lines.
NOTE: If the outdoor furnace supply and return
lines are not insulated properly, or if other
brands of insulated piping are used, there can be
excessive heat loss. This heat loss can greatly
increase the fuel consumption.
NOTE: If it is unavoidable that the supply and
return lines will run through an area of ponding
water, use ThermoPEX instead of other materials.
ThermoPEX should also be used for aboveground or winter installations, and if the area is
likely to be affected by compaction.
Above Ground or Winter Installations
For above ground or winter installations in which
the supply and return lines can not immediately be
buried underground, Central Boiler recommends using
ThermoPEX. Be sure that both the insulation and the
supply and return lines will not be exposed to ultraviolet
rays. The ThermoPEX black exterior jacket has UV
protection but the insulation and water lines inside do
not. Use a ThermoPEX termination cap at each end of
the installation to protect and seal the insulation from
water.
NOTE: If an above ground installation is
temporary, bury the ThermoPEX as soon as
conditions permit (e.g., once the ground has
thawed).
NOTE: If ThermoPEX is installed temporarily
above ground, provisions should be made (i.e.,
a firestop) to prevent possible risk of fire coming
into contact with the ThermoPEX. ThermoPEX
is constructed of materials that can burn and
transfer a fire.
CAUTION
If ThermoPEX is installed temporarily above
ground, do not cover with combustible materials
(e.g., stray, hay, leaves, etc.).
If installed next to the building being heated, the supply
and return lines can be installed above ground provided
they are properly insulated and not exposed to ultraviolet
rays (see Fig. 17 as an example).
Section 6 - System Installation
17
Digging the Trench
WARNING
Before digging, be sure to call for utility locator
service.
NOTE: The base on the back of the outdoor
furnace is removable if necessary for connecting
the supply and return lines to the outdoor furnace.
Fig. 19
The trench depth for ThermoPEX should be between
10" and 28" (25 and 71 cm).
Fig. 18
Underground Electric Wire
A 12-2 (two wires plus ground) underground rated wire
CAUTION
should supply the outdoor furnace with electricity. A
heavier gauge wire may be needed if the run is over 200 Allow for expansion and contraction of the
feet (61 meters). Check local codes and requirements. A supply and return lines at each end. Without
an allowance for expansion and contraction,
20-amp circuit is recommended.
Connecting to Existing Heating System
1. Make an entrance into the building(s) where the
supply and return lines are to enter.
2. Lay the ThermoPEX assembly in the trench and
feed one end into the building. Apply sealant around
the supply and return lines where they enter the
building.
3. Purge the supply and return lines before connecting
any fittings to ensure there is no debris or foreign
matter present.
NOTE: All holes made in basement or building
walls must be sealed completely to prevent water
from entering the building.
4. Close all valves on the outdoor furnace.
5. Install fittings to allow pressure-testing of both
supply and return lines. Pressurize with 50 psi (3.5
kg/cm2) of air; then check after 30 minutes to see if
pressure has dropped. A drop in pressure indicates a
leak; repair as necessary.
the lines may kink or the fittings may be pulled
apart, causing an immediate water loss from the
outdoor furnace. Central PEX water lines can
have an expansion and contraction rate up to
.095" per each 100 ft and each 10°F (2.4 mm/30
m/5.5˚C).
7. Make sure there are no leaks in the supply and return
lines; then backfill the trench.
NOTE: Do not backfill the trench until the supply
and return lines have been tested to ensure there
are no leaks.
Backfilling Water Line Enclosure
Using gravel or small rock, backfill the perimeter of the
water line enclosure to the top, inner edge of the base
(Fig. 20) to keep out rodents. Install the back and side
panels.
Fig. 20
6. Connect the supply and return lines to the outdoor
furnace and the existing heat emitter(s). Fig. 19
shows some of the PEX fittings and tools used in
making connections.
18
Section 6 - System Installation
CIRCULATION PUMPS
NOTE: The direction of water flow is very
important for the proper operation of the outdoor
furnace. Installing a swing check valve in the
return line can prevent possible reverse flow.
Fig. 22
Water Flow
For a single building using a water-to-air heat exchanger
system with a domestic water heater, the direction of
water flow must go from the hot outlet on the outdoor
furnace to the lower side fitting of the domestic water
heater exchanger, to the lower fitting of the heat
exchanger on the existing furnace, and then to the return
port of the outdoor furnace.
NOTE: if there is a high heat draw with a single set
of lines, a wraparound pump (as shown in Fig. 21)
may be needed in order to keep the supply water
temperature the same temperature indicated by
the FireStar controller.
NOTE: Some systems may have different flow
patterns.
Access to Ports on Furnace
Access to the hot supply and return ports is gained by
removing the access panels on the lower right-hand
side and back of the furnace. There are two hot supply
and two return ports on the furnace. This configuration
allows for mounting the circulation pumps on the
furnace (Fig. 22).
There are eight knock-out tabs on the floor panel of
the furnace to accommodate the water lines. These
align with the hollowed-out area in the foundation
specifications (Fig. 6). The pump access area in the back
right corner must align with the blocked out area of the
foundation.
Installing Circulation Pumps
The Taco 009 is a medium flow, high head pressure
pump that requires an adequate amount of pressure on
the outlet side to prevent the motor from overloading.
Fig. 21
Maxim
with Wrap-around-pump Installed
Area of Focus
FIRE STAR
TM
b y C en t ral B oi ler
Water Temp
100%
Heat Output
60%
HIGH
65%
5%
MEDIUM
20%
LOW
1%
Air Adjust
Ignition
Auger
Hold to
Prime
Hold
to Light
Auto Relight
Enabled
Press
Twice
to Clean
Press
Twice
for Auto
Relight
Power
Clean Out
Mode
p/n 9507
1-1/4
1-1/4
1-1/4
1-1/4
1-1/4
Side
556
410
1-1/4
380
225
382
198
5871
1-1/4
1334
1-1/4
1-1/4
1-1/4
5926
274
Side View
Section 6 - System Installation
Rear
Parts List
Qty p/n
Description
2
1
2
1
3
2
2
1
2
2
2
1
6
Taco 007 Pump
Ball Valve, 3/4"
Isolation Flange, 3/4"
Isolation Flange Kit, 1-1/4"
90° Street Elbow, 3/4"
MPT to PEX, 1-1/4"
90°PEX Elbow, 1-1/4"
Ball Valve, 1-1/4"
Power Supply Cord, 32"
PEX Adapter, 1" x 3/4"
90° PEX Elbow, 1"
Swing Check Valve, 1-1/4"
Stainless Steel Clamp
Crimp Ring, 1"
171
198
224
225
274
380
382
410
556
1330
1334
5871
5926
Parts and accessories sold separately.
Pump size may vary.
171
224
Rear View
19
The Taco 014 is a high flow, high head pressure pump
that requires an adequate amount of head pressure on
the inlet side to prevent cavitation. Therefore, a Taco
014 may need to be mounted lower near the base of the
furnace, and on the 1-1/4" bung.
Fig. 24
The Taco 007 is a medium to high flow, low head
pressure pump. In a very low-resistance system (e.g.,
short length of supply and return lines, only a flat
plate heat exchanger, etc.), the 007 pump may need to
be mounted lower near the base of the furnace or on
the 1-1/4" bung to prevent cavitation at high water
temperatures.
NOTE: See the Hydronic Component Selection
Guide (p/n 2482) for more detailed information.
The following guidelines must be adhered to when
installing the circulation pump(s).
WARNING
Maximum load of the outlet on the outdoor
furnace is 10A, 120VAC, and 60Hz.
A.The pump motor must be installed in a horizontal
position.
B.The junction box must not be located below the
pump motor (see Fig. 23). If necessary, remove the
four screws and rotate the pump body.
Fig. 23
NOTE: At least one circulation pump must run
continuously to ensure proper operation of the
outdoor furnace.
The circulation pump(s) must be installed in the
supply line(s) with the arrow on each pump pointed
away from the outdoor furnace. In order to avoid
circulation problems, do not install the pump(s) in the
return line(s).
Fig. 25
C. Do not operate the circulation pump until the entire
system has been filled with water and checked for
leaks or the pump may be damaged.
D. Insulate the areas around the supply and return lines
(Fig. 24) and pump(s) being careful not to block the
area around the louvers; then install and secure the
side and back panels.
The pump(s) must be located near the base of the
outdoor furnace if the system has a high-flow pump or
very low resistance on the outlet side of the pump. For
example, if the outdoor furnace is 20 feet (6 meters)
from the building and pumping water through oneinch pipes, a heat exchanger, and back to the outdoor
furnace, the pump needs to be mounted with four feet of
water above the pump.
NOTE: See the Hydronic Component Selection
Guide (p/n 2482) for more detailed information.
20
Section 6 - System Installation
Installing the circulation pump(s) at the outdoor furnace
is recommended, but required if the building being
heated is higher than the outdoor furnace or if there is a
large rise in the water lines between the outdoor furnace
and building (see Fig. 26 and 27). Hot water boils at a
lower temperature when pulled uphill (because it is at
a lower pressure); therefore, hot water must be pushed
uphill to ensure proper circulation.
NOTE: The thermostatic valves illustrated
throughout the manual may vary from your
installation. See the installation instructions
provided with the thermostatic valve.
CAUTION
DO NOT operate the outdoor furnace with the
water temperature less than 150˚F (65˚C).
A thermostatic valve must be installed on each set
of supply and return lines in the system to maintain
the outdoor furnace water temperature above 150˚F
(65˚C). Operating the outdoor furnace with the water
temperature less than 150˚F (65˚C) may result in more
condensation in the firebox that can lead to corrosion.
Fig. 26
If not mounted on the outdoor furnace, the circulation
pump(s) must be mounted 4 to 5 feet (1.2 to 1.5 m)
lower than the top water level in the outdoor furnace
(see Fig. 27).
It is recommended that the water temperature setpoint
of the furnace be set to 185˚F (85˚C) to decrease the
likelihood of the water temperature falling to 150˚F
(65˚C). As a result, the outdoor furnace will operate
with a greater efficiency and require less maintenance.
Failure to follow proper operating instructions may
result in furnace damage.
Fig. 28
Ball Valve
Fig. 27
Water Level
Ground
Level
Building to be heated
Hot Supply from Pump
on Outdoor Furnace
Hose Bib
Thermostatic Valve
4 ft. min.
Pump must be installed
in the hot supply line
and may be located
inside this building
Return to
Outdoor Furnace
© 2015 Central Boiler
Shut-Off Valves
Shut-off valves should be installed on both sides of each
pump so if it becomes necessary to repair or replace the
pump, the pump can be isolated.
Filters
A Y-strainer or filter may be installed at the outlet side
of the pump to remove foreign particles which may be
present in the water. Always install Y-strainers with the
cleanout in the lowest position.
Thermostatic Valves
NOTE: A 3/4" thermostatic valve must be installed
on each set of supply and return lines or warranty
can be voided.
NOTE: For additional thermostatic valves, or
for 1-1/4" thermostatic valves, contact your
authorized Central Boiler dealer.
Section 6 - System Installation
21
MAXIM THERMOSTATIC VALVE - HOW IT WORKS
NOTE: With higher heat loads, it may be necessary to change the water temperature setpoint on the
FireStar controller to be no less than 185˚F.
NOTE: When the thermostatic valve allows a trace flow, enough water will pass through for the
backup indoor heating system to backfeed heat to the outdoor furnace and water lines, protecting
against freezing.
22
Section 6 - System Installation
Purging Air from the System - Manual Air
Bleeders
Manual air bleeders may be installed in the high points
of the water lines where air may get trapped and cause
circulation problems. Water can be pumped to levels
higher than the outdoor furnace as long as the pump
is pushing the water to the higher level and there are
no air leaks in the system. Additionally, air should be
purged from the system using pressurized domestic
water and a hose with two female ends (see Fig. 29).
WARNING
The outdoor furnace vent cap must fit loosely on
the vent opening. Do not force the cap down or
try to seal it tightly onto the vent pipe. Do not
extend or restrict the vent pipe or opening. DO
NOT ALLOW THE OUTDOOR FURNACE TO BE
PRESSURIZED.
If any auto float vents are present in the system, they
must be capped off tightly to prevent air from entering
the system.
Fig. 29
WATER HEATER INSTALLATION
WARNING
DO NOT disable or remove any safety reliefs or
controls. Turn off the power to the water heater
before installation.
When installing a domestic hot water heat exchanger,
the hot supply line from the outdoor furnace should be
plumbed first to the water heater heat exchanger and
then to the balance of the heating system.
A manual 3-way valve may be installed so that during the
non-heating season, the water heater may be operated
without operating the entire heating system (see Fig.
30). A tempering valve (or thermostatic mixing valve)
is to be installed in the hot water outlet from the water
heater. Install a tee in a fitting on the top of the water
heater (see Fig. 32) for the hot water heat exchanger.
NOTE: If the water heater has been in service,
flush the water heater prior to installing the hot
water heat exchanger. Anode rod residue or
other sediments in the water heater may plug the
heat exchanger.
NOTE: Some gas water heaters are equipped
with a high water temperature probe that is
connected to the gas valve. When the water
temperature exceeds the high limit, the gas valve
enters a non-resettable lock out condition. This
requires replacement of the entire valve. The
installer must determine if this type of valve is
present before installation of a water-to-water
heat exchanger.
CAUTION
Costly maintenance may be incurred if steps
are not taken during installation to reduce or
eliminate the possibility of the water temperature
in the water heater exceeding the high limit.
Fig. 30
Thermostatic
Mixing Valve
Hot Supply
M
This horizontal assembly
must not exceed a height
of 4 inches (10 cm) above top
of water heater.
R
H
C
NOTE
Use softened water if
water has a high mineral
content to avoid plugging
the heat exchanger.
Water-to-Water
Heat Exchanger
NOTE
Optional Bypass
Valve
Bypass Line
NOTE: See the Hydronic Component Selection
Guide (p/n 2482) for more detailed information.
Hot Supply from Pump
on Outdoor Furnace
1"
Central
PEX®
Existing
Water
Heater
If outdoor furnace is not
being used for an
extended period of time
to heat water, this valve
should be closed to
prevent heat loss from
the water heater through
the side arm exchanger.
NOTE
Outdoor furnace water
temperature setpoint
should be set at 185˚F
(85˚C) minimum.
NOTE
Thermostatic Valve
Return to Outdoor Furnace
NOTE
Installer must comply
with all applicable codes
and regulations.
For illustration purposes
only, water heater styles
may vary.
A pump must be installed
in the hot supply line
between the outdoor
furnace and thermostatic
valve.
© 2015 Central Boiler
Section 6 - System Installation
23
EXISTING FORCED AIR INSTALLATION
When the Maxim is installed in conjunction with an
existing forced air system, a water-to-air heat exchanger
is mounted in the plenum or duct work of the existing
furnace. Heated water from the outdoor furnace either
continuously flows through the water-to-air heat
exchanger or is diverted through a 3-way zone valve.
When the thermostat senses the need for heat, the fan
on the existing furnace forces air through the heat
exchanger, transferring heat throughout the existing
ductwork.
Following are several important items for this type of
installation.
• Plenums installed to the furnace must be
constructed of metal in accordance with NFPA
90B, 2-1.3.
• If an air conditioning coil is located in the plenum,
the heat exchanger should be mounted between
the fan and the air conditioning coil so the heat
exchanger will not freeze when the air conditioner
is being used.
• The heat exchanger should not be installed in the
cold-air return of the existing forced air furnace
because components of the existing furnace could
overheat.
• The heat exchanger may be mounted either
horizontally or vertically with the outlets on the
side (see Fig. 31).
Fig. 31
• The lower fitting is the inlet/hot supply from the
outdoor furnace and the top fitting is the outlet/
return back to the outdoor furnace.
• It is best to install a heat exchanger that fits the
plenum.
• If the plenum is larger than the heat exchanger, it
should be mounted in the center without gaps on
the sides that would allow air to flow around the
heat exchanger. All air must be directed through
the face of the exchanger. Air flow deflectors need
to be installed in the plenum on the outlet side of
the heat exchanger if air flow is funneled into the
heat exchanger.
• Be sure to consider the airflow through the
ductwork so air circulation is not blocked off to
parts of the building.
• Adding a heat exchanger coil in the hot air
plenum or ductwork of the existing furnace may
decrease the air flow in the system. The existing
heat emitter(s) (gas or electric) should be operated
before adding the heat exchanger.
• The air temperature rise should be measured with
the heat emitter(s) running for an adequate amount
of time to get a stabilized temperature reading.
The heat exchanger can then be installed in the
system. The existing heat emitter(s) should be
operated again and the air flow should be adjusted
to maintain the same temperature reading. The air
flow may have to be increased to accomplish this.
• On a belt-drive system, the blower pulley and/
or motor pulley may be changed; however, the
electrical current flowing through the motor must
not be changed to exceed the nameplate rating.
A larger blower motor may be used. On a directdrive system, in most cases the blower motor will
not need to be replaced; however, the speed of the
blower motor may have to be increased.
CAUTION
When installing the heat exchanger, be sure
none of the existing system safety controls are
disabled.
NOTE: Any electrical installation should be done
by a certified electrician in accordance with all
applicable codes.
• In all applications, the heat exchanger must be
mounted level from front to back, with the outlets
on the side. If the outlets are positioned upward or
if the exchanger is not level, an air lock can restrict
the water circulation and reduce the amount of
heat transfer.
24
• Due to the internal circuitry of some thermostats,
a snap disc temperature control may have to be
installed on the heat exchanger manifold to provide
an interlock for the air conditioner. This prevents
the air conditioner from operating when the water
temperature is higher than 140°F (60˚C).
Section 6 - System Installation
Fig. 32
WATER-TO-AIR HEAT EXCHANGER
AND WATER HEATER SYSTEM
NOTE: A certified electrician must
perform the electrical installation.
Thermostatic
Mixing Valve
Heat
Exchanger
M
R
This horizontal assembly
must not exceed a height
of 4 inches (10 cm) above top
of water heater.
H
C
Hot Supply
Plenum
Water-to-Water
Heat Exchanger
Existing
Forced Air
Furnace
Bypass Line
NOTE
A pump must be installed in the hot
supply line between the outdoor furnace
and thermostatic valve. Outdoor furnace
water temperature setpoint should be
set at 185˚F (85˚C) minimum.
Optional Bypass
Valve
1"
Central
PEX®
Hot Supply from Pump
on Outdoor Furnace
Existing
Water
Heater
NOTE
Installer must comply with all
applicable codes and regulations.
For illustration purposes only,
water heater styles may vary.
Thermostatic Valve
Return to Outdoor Furnace
White
Neutral
White
Fan
Switch or
Snap Disc
on Furnace
Neutral
Fan Speed Tap Wires
(Connect Prefered Speed Tap Wire)
Black Brown
Red
White
White
Black
Black
Ground, Hot and
Neutral Wires 110-V Line
at Furnace
Voltage
EM
ST
SY
N
RUN
HOL
D
FA
ON
AUTO
L
COO
OFF
HEAT
Fan Relay
Y
24-Volt Thermostat
C is optional
with batteries
M
E PRG
Ground
Transformer
Thermostat
p/n 588
(O/B)Y2
E/W1 R
C
TIM
L
Y1
NOTE
On multi-speed fans, cap and
tape off any extra wires.
W2
G
For illustration purposes only.
Section 6 - System Installation
C
R
G
G
R
NOTE
This configuration allows
use of a 24-volt thermostat
on older forced-air units
with no control board.
© 2015 Central Boiler
25
Fig. 33
Forced Air Heating and Water Heater System
p/n 108
Supply
p/n 8200008
p/n 5926
Wood Heat
Thermostat
p/n 1330
PEX
Existing
Thermostat
Return
p/n 5926
p/n 5349
p/n 5348
p/n 199
p/n 117
p/n 255
p/n 200
p/n 372
M
R
H
p/n 116
C
116
TM
STAR
Boiler
FIRE
by
Central
5%
Temp
Water
Output
Heat
60%
LOW
100%
MEDIUM
HIGH
1%
20%
Air
Auger
Adjust
65%
Ignition
to
Hold
Prime
to
Press
Out
Twice
Clean Clean
Mode
p/n
9507
Hold
Light
to
Press
Twice
Auto
for
Relight
Power
Relight
Auto
Enabled
255
p/n 116
p/n 591
p/n 118
p/n 1330
p/n 133
p/n 199
p/n 5349
p/n 5348
117
p/n 2441 & 2491
NOTE
NOTE
Installer must comply with all applicable
codes and regulations.
p/n 2443
A pump must be installed in
the hot supply line between
the outdoor furnace and
thermostatic valve. Outdoor
furnace water temperature
setpoint should be set at
185˚F minimum.
Optional Copper
Fittings
(not included in kit)
116
p/n 116
p/n 1330
p/n 116
p/n 255
p/n 117
p/n 199
p/n 5349
p/n 5348
2013 Central Boiler
26
Section 6 - System Installation
Thermostatic Controls
There are several methods for installing thermostatic
controls for this type of installation.
1.If the forced air furnace has connections for
control of the blower from a thermostat or switch,
the simplest method is to add a second 24-volt
thermostat. Wire the thermostat to the forced air
furnace so that upon a call for heat, the thermostat
closes the connection between power (usually 'R'
or red) and the fan terminal (usually 'G' or green).
By setting the new thermostat to the desired room
temperature, it will control when the blower
operates, drawing heat from the outdoor furnace.
The existing thermostat should be set a few degrees
below the new thermostat. This setting will be the
temperature at which the existing forced air heating
system will operate if the outdoor furnace is out of
fuel. Refer to Fig. 34 for one possible arrangement.
2. An alternative method is to install a line voltage
thermostat to control the blower on the forced air
furnace. In this installation, a 120-volt wire is run
from the thermostat to the forced air furnace. One
wire is connected to the hot (line feed) and the
other wire is connected to the forced air furnace
blower wire. A low water temperature switch may
be installed to shut off the blower if the temperature
of the water is too low. The switch is connected
in series to the wire coming from the line voltage
thermostat and must be installed so that it does not
affect the forced air system thermostat.
NOTE: If the low water temperature switch
is not installed, the fan will run continuously
even when the outdoor furnace is out of fuel.
This will keep the water in the outdoor furnace
approximately the same temperature as the air
in the house (to prevent the water in the outdoor
furnace from freezing). This will also work with
the thermostatic valve installed.
Fig. 34
Section 6 - System Installation
27
HEATING MULTIPLE ZONES OR BUILDINGS
A single pump and manifold may be used to heat
more than one zone as long as the return water can be
maintained above 150°F (66˚C). If the return water
temperature can not be maintained above 150°F (66˚C),
then a separate pump should be used for each zone. A
thermostatic bypass valve must be installed to ensure
that the water temperature in the outdoor furnace is
maintained above 150˚F (66˚C).
If a manifold is used, a swing check valve (p/n 296)
should be installed in the line at the outlet of the pump.
The swing check valve must be installed in a vertical
position with the direction of flow as designated by
the arrow on the swing check valve. This will prevent
reverse circulation and loss of heat on multiple zones if
one pump fails. Hose bibs (p/n 199) should be installed
on each supply and return manifold to allow for purging
air from the zones.
The Maxim offers two sets of outlets (for up to two
zones or buildings without the need for manifolds)
for mounting up to two pumps. Fig. 35 illustrates one
possible configuration.
NOTE: If the outdoor furnace is unable to
maintain a water temperature of 150˚F (66˚C)
or higher, inspect the thermostatic valve and
replace if necessary.
NOTE: A properly-sized backup furnace or boiler
should be configured to provide heat if the
outdoor furnace is out of fuel or the heat load
exceeds the capacity of the outdoor furnace.
Fig. 35
Heat for Multiple Buildings
28
Section 6 - System Installation
HYDRONIC INSTALLATIONS
NOTE: It is recommended that the circulation
pump in all hydronic systems be located in the
hot supply line, not in the return line (see Fig. 36
and 37).
Evaluate the existing hot water heating system before
starting the installation. If the existing hot water heating
system has been unable to maintain the temperatures
in the home at any time during cold weather before
installing the outdoor furnace, then the hot water heating
system is not adequate. More baseboard or other type of
heat exchanger must be added.
If a water-to-water heat exchanger is to be used with
an existing heating system, the existing heating system
must be able to adequately heat the building with a
water temperature of approximately 165°F (74˚C).
Some existing finned tube baseboard hot water heating
systems are designed to operate with water temperatures
up to 220°F (104˚C) or higher.
If the existing heating system is marginal or designed to
operate with water temperatures above 165°F (74˚C),
there are alternative installation procedures that will
make the existing system work very well with the
outdoor furnace. These include:
1. Add more finned tube water baseboard heaters or
panel radiators.
2. A water-to-air heat exchanger with a thermostatically controlled fan can be installed in the lower part
of the building being heated (Fig. 36). This can
increase the amount of heat added to the building,
helping to maintain a constant temperature. This
heat exchanger can be added in the return line of the
system after the water-to-water heat exchanger.
3. An additional radiant heating circuit can be added to
heat areas that require additional heat.
Fig. 36
Water-to-Water Shell & Tube Exchanger with Existing Boiler
Circulating
Pump
This valve should be closed
if the outdoor furnace is not
being operated in the summer.
Return
M
R
H
C
This pipe must not exceed a
height of 4 inches (10 cm)
above top of water heater.
NOTE
Outdoor furnace water temp
setpoint should be set at
185˚F (85˚C) minimum.
Existing
Boiler
Supply
Flow check or zone
valve here will prevent
thermal circulation and
overheating of
building. It is recommended that the
circulation pump in all
hydronic systems be
located in the hot
supply line, not the
return line.
Water-to-water
Heat Exchanger
NOTE
NOTE
A pump must be installed in the hot
supply line between the outdoor furnace
and thermostatic valve.
Existing
Water
Heater
Hot Supply from Pump
on Outdoor Furnace
Return to Outdoor Furnace
Section 6 - System Installation
Installer must comply with
all applicable codes and
regulations.
© 2015 Central Boiler
29
Pressurized Water System Installations
Water-to-Water Heat Transfer System
To keep the existing system pressurized, a plate
exchanger or tube & shell water-to-water heat exchanger
installed in the return line of the existing system may be
used (see Fig. 37 and 38). The water from the existing
system passes through the heat exchanger when the
thermostat calls for heat. The water from the outdoor
furnace circulates through the other side of the heat
exchanger continuously.
It may be necessary to lower the water temperature
at which the burner in the existing boiler starts to a
setting that prevents the burner in the existing boiler
from cycling on when the outdoor furnace is heating
the home. Another option is to install a thermostatically
controlled interlock switch that prevents the burner
in the existing boiler from operating when the water
temperature in the outdoor furnace is above 150˚F
(66˚C).
Water-to-water heat exchangers will produce transfer
temperatures approximately 20ºF (11˚C) less than the
outdoor furnace water temperature; therefore if the
outdoor furnace water temperature is 185°F (85˚C),
it will produce approximately 165°F (74˚C) of water
temperature transfer. The temperature controller on the
outdoor furnace may be adjusted to allow the outdoor
furnace to reach water temperatures up to 195ºF (91˚C).
Each system will vary in water temperature transfer
depending upon the heat load of the existing heating
system.
The addition of a wraparound pump with a waterto-water heat exchanger (see Fig. 37) may increase
heat transfer by allowing circulation continuously
through the existing boiler and heat exchanger. This
will maintain the maximum temperature in the heat
exchanger for heat transfer to the existing boiler. Note
the water flows in opposite directions through the heat
exchanger.
With this type of installation, the exchange temperature
may be more than 165°F (74˚C) and may eliminate the
need for additional baseboard heaters, panel radiators
or heat exchangers.
When installing water-to-water heat exchangers, be
sure to flush any rust particles or sediments out of the
existing boiler and install a Y-strainer as illustrated in
Fig. 37. Also be sure to add Corrosion Inhibitor Plus™
(p/n 1650).
A Taco 007 or 014 pump can be used as a wraparound
pump when a plate exchanger is installed. A Taco 009
or 014 pump should be used when a shell and tube heat
exchanger (i.e., p/n 148, 151 or 177) is installed.
NOTE: See the Hydronic Component Selection
Guide (p/n 2482) for more detailed information.
Fig. 37
Plate Exchanger
30
Section 6 - System Installation
Vented System Installation
The Maxim may be connected directly into an existing
hot water system, changing it to an atmospheric vented
system.
NOTE: Any changes in the existing boiler and/
or system should be done by a certified installer
in accordance with applicable codes. Be sure
the system water is properly maintained with
Corrosion Inhibitor Plus™ (see Water Quality
and Maintenance section).
The hot supply line from the outdoor furnace can be
connected into the top of the existing boiler and returned
to the outdoor furnace from the bottom of the boiler
(see Fig. 38). Use one pump to continuously circulate
the water from the outdoor furnace through the existing
boiler and back to the outdoor furnace.
CAUTION
The outdoor furnace must NEVER be pressurized.
The vent cap must always be loose. Do not
extend the vent pipe. The outdoor furnace will be
damaged if it is pressurized.
When the existing system is connected to the outdoor
furnace as illustrated in Fig. 38, the circulating pump(s)
in the existing system must be located in the hot supply
line(s), not in the return line(s). A flow check or zone
valve will prevent thermal circulation and overheating
of building.
It is very important to eliminate all air and water leaks
(valve packings, bleeders, etc.) and purge all air from
the existing system.
1. After filling the outdoor furnace (see Initial StartUp Procedures section) and existing system with
water, purge the air from the indoor system by
closing the valves on the outdoor furnace; then
pressurize the indoor system with water from the
domestic water line.
CAUTION
Do not apply more pressure to the indoor system
than the pressure relief valve on the existing
boiler is rated for.
2. Bleed air from the pressurized indoor system; then
operate the circulating pump(s) on the indoor system.
Perform this procedure twice. If any auto float vents
are used in the existing system, they must be capped
off tightly after the air bleeding is completed. This
eliminates the possibility of allowing air to enter
after the system is depressurized.
3. When the indoor system is completely purged of air,
close the valve on the water line used to pressurize
the indoor system. If any air is trapped in the
system, it can reduce water flow. This will prevent
the system from heating properly.
4. Open valves on the outdoor furnace, turn on the
pump and proceed to start the fire in the outdoor
furnace.
Fig. 38
DIRECT CONNECTION TO EXISTING BOILER
Baseboard Heat Return
M
R
H
C
Water
Heater
TM
STAR
Boiler
FIRE
by
Central
5%
Output
Heat
60%
Temp
Water
LOW
100%
MEDIUM
HIGH
1%
20%
Air
Auger
Adjust
65%
Ignition
to
Hold
Prime
to
Press
Out
Twice
Clean Clean
Mode
p/n
9507
Hold
Light
to
Press
Twice
Auto
for
Relight
Power
Relight
Auto
Enabled
2-way
Zone Valve
Flow check or zone
Circulating valve here will prevent
Pump
thermal circulation and
overheating of building.
It is recommended that
the circulation pump in
all hydronic systems be
located in the hot
supply line, not the
return line.
Existing
Boiler
Vented
Note
Outdoor furnace water
temperature setpoint should
be set at 185˚F minimum.
Note
A pump must be installed in the hot
supply line between the outdoor furnace
and thermostatic valve.
Note
Installer must comply with all applicable
codes and regulations.
© 2013 Central Boiler
Section 6 - System Installation
31
Direct Circulation Baseboard Installation
Baseboard heaters, as either the main source of heat or
as supplements to forced-air or boiler applications are
easily plumbed into the water lines from the outdoor
furnace.
Refer to Fig. 39 and 40 for proper plumbing methods.
Fig. 39
This horizontal assembly
must not exceed a height
of 4 inches (10 cm) above
top of water heater.
NOTE
Outdoor furnace water temp
setpoint should be set at
185˚F (85˚C) minimum.
Fig. 40
NOTE
Outdoor furnace water temp
setpoint should be set at
185˚F (85˚C) minimum.
This horizontal assembly
must not exceed a height
of 4 inches (10 cm) above
top of water heater.
Return to
Outdoor Furnace
32
Section 6 - System Installation
Radiant Floor System Installations
Radiant heat can be a great option for new construction
or for adding to an existing home if the floor joists are
exposed (as in an unfinished basement). Piping may
be installed in a wide variety of configurations and
locations including, but not limited to, the following:
• In a concrete slab
• Within the subfloor system (e.g., Gyp-Crete®)
• Within the floor joist system
• Within the walls or ceilings
Carefully consider each of the following before
beginning construction and installation:
1. When installing piping between floor joists (16" or
41 cm on center) run two 1/2" pipes between each
joist. Insulate below the piping to prevent excessive
heat in the lower level.
2. Proper insulation is key to effective radiant heating
and controlling large heat demands. Heat from this
type of system radiates equally in all directions.
As an example, if piping is installed in a slab,
the ground below the slab must be dry and wellinsulated. If not properly insulated, nearly 50% of
the heat will be wasted warming the ground below
the slab. Two inches (5 cm) of blueboard insulation is
recommended. Two 1" (2.5 cm) layers of blueboard
can be used. This allows lapping of the joints in the
4' x 8' (122 x 244 cm) sheets.
NOTE: Do not use beadboard (expanded
polystyrene), bubble foil or roll-out foam
insulation.
NOTE: A minimum of one inch (2.5 cm) of
insulation should be used. Two inches (5 cm) of
insulation with vapor barrier below the insulation
is recommended.
Fig. 41
3. Areas with high water tables need to be prepared
properly to prevent contact between the ground
water and insulation.
NOTE: For examples of radiant heating systems
using 1/2" piping in the loops, refer to Fig. 42
through Fig. 45.
4.The spacing of each circuit is 12" (30.5 cm)
between pipes. The water circulates in opposite
directions to provide an even distribution of heat.
The mixing valve regulates the temperature of the
water circulating through the loops by mixing return
water with the hot supply water. In applications
where high heat loss is expected, loop spacing may
be reduced to 10" (25 cm) or less. If additional
information is desired, contact your dealer.
NOTE: The longer the loop length, the lower the
flow rate and the lower the heating capacity.
Loop lengths greater than 350 feet (107 m) are
not recommended.
NOTE: The temperature of the water used in
radiant heating should be determined by the
installer in accordance with the application.
5. It is not uncommon that it can be very difficult to
get a concrete slab up to temperature in late fall or
early winter in a new building that is not completely
sealed and not well insulated. Once the building is
completely sealed and well insulated, bringing the
slab up to temperature can still take a considerable
amount of time and fuel; however, once warm, fuel
consumption will be reduced if the concrete slab
and building are insulated properly .
NOTE: For zone installations, refer to Fig. 42
(multi-zone) or Fig. 44 (single zone).
Radiant Floor Heat
(For Slab on Grade or Basement)
Hot Supply Return
NOTE: If the temperature of the
concrete slab is below freezing
(32˚F), there must be adequate
antifreeze in the system, or the
slab must be pre-heated, before
water is circulated through the
radiant slab system.
Basement
Insulation
Insulation
Slab
Vapor Barrier
Insulation
Slab on grade
Wire
Mesh
2" Blueboard Styrofoam®
is recommended (minimum
of 1" Blueboard Styrofoam®).
Section 6 - System Installation
Ground
Level
Plate
Poly Vapor
Barrier
Slab
Footing
Soil/Sand
Slab Insulation
Insulation
Poly Vapor
Barrier
Footing
Plate
Ground Level
Soil/Sand
© 2013 Central Boiler
33
Fig. 42
Fig. 43
34
Section 6 - System Installation
Fig. 44
Fig. 45
Section 6 - System Installation
35
Pool and/or Hot Tub Heating
Valves should be installed so the heat exchanger can be
isolated and bypassed when shock-treating or adding
chemicals to a pool or hot tub (Fig. 46). Incorrect
chemical concentrations can cause rapid corrosion to
the heat exchanger. Bypassing the heat exchanger is
recommended until the pH has stabilized between 7.2
and 7.8.
If the swimming pool or hot tub is salt water treated, the
heat exchanger should be a shell and tube type (p/n 148,
151 or 177). See the Hydronic Component Selection
Guide (p/n 2482) for more detailed information.
CAUTION
WARNING
Do not use automotive or ethylene glycol
antifreeze in an outdoor furnace connected to
a swimming pool heat exchanger as a damaged
heat exchanger may cause severe personal
injury, death, or substantial property damage.
CAUTION
Do not operate the outdoor furnace frequently
or for extended periods of time with the water
temperature below 150˚F (65˚C) as this will result
in more condensation in the firebox that can lead
to corrosion.
Do not install a swimming pool heat exchanger
inside a home or building below the level of the
pool as a damaged heat exchanger may result in
extensive flooding and draining of the pool.
Fig. 46
NOTE
Outdoor furnace water temp
setpoint should be set at
185˚F (85˚C) minimum.
36
Pools and hot tubs typically have high
water flow rates, from 30-50 gpm (114-189
lpm) for residential and higher for commercial
applications. Because the MP Series is a high
efficiency heat exchanger and does not require the full
pool gpm flow, a bypass balancing valve must be used to
bypass a portion of the pool water. There should be a shut-off
valve installed on the supply and return line to and from the
pool. Close these valves and fully open the bypass balancing
valve when chemically treating (“shocking”) the pool or hot tub
to stop the flow of the low pH water to the heat exchanger.
These valves can be opened only after the pH has reached
the safe level as recommended by the pool or hot tub
manufacturer. Return the bypass balancing valve to the
previously adjusted position.
Section 6 - System Installation
SECTION 7 – FILLING SYSTEM WITH WATER
AND PURGING AIR
Before firing the outdoor furnace for the first time,
perform the following important steps:
1. Check for leaks. Close the valves on the outdoor
furnace before checking for leaks. Do not pressurize
the outdoor furnace. Pressure-test the entire
plumbing system. Apply 50 psi (3.5 kg/cm2) of
air pressure for thirty minutes and closely monitor
for any pressure loss. Inspect all fittings and hose
ends for any signs of leakage using leak detection
solution (leak soap); repair as necessary.
2. Cover Supply and Return Lines. Backfill the
trench for the supply and return lines. Enclose the
area where the supply and return lines enter the
outdoor furnace. Do not leave the PEX hot supply
and return lines exposed to sunlight as exposure to
UV rays will damage them.
3. Add Corrosion Inhibitor Plus™. Add Corrosion
Inhibitor Plus™ (p/n 1650) through the vent pipe
on the outdoor furnace before filling with water
to immediately begin to protect the steel. Refer to
Water Quality and Maintenance.
4. Turn the FireStar controller on by pressing the
Power
button. The LED display should flash
to indicate that the water level is below the
sensor.
5. Fill with water, purge air from system and verify
flow direction of the water. See Filling Outdoor
Furnace with Water and Purging Air for details.
6. Install the vent cap. The vent cap must fit loosely
over the outdoor furnace vent.
FILLING OUTDOOR FURNACE WITH WATER
AND PURGING AIR
NOTE: The items referred to in this procedure
correspond to the items in Fig. 47. Refer to Fig.
47 when performing these steps.
All air must be purged from the water lines when filling
the system. Also, the circulation pump(s) must be
installed in the hot supply line(s).
NOTE: If using the valve on the water heater to
fill the outdoor furnace, flush the water heater
to remove all sediment before filling the outdoor
furnace.
NOTE: If the outdoor furnace is being filled with
water when the temperature is below freezing,
circulate the water immediately after filling to
prevent freezing the water lines.
NOTE: Be sure to fill the outdoor furnace with
water of good quality (softened water, if possible).
See Water Quality and Maintenance section.
Use the procedure in this section to fill the outdoor
furnace with water and purge the air from the system.
All valves in the outdoor furnace system that allow
circulation through each circuit should be open before
starting. Perform this procedure on each pump circuit
from the outdoor furnace.
NOTE: Add Corrosion Inhibitor Plus™ (p/n 1650)
through the 2-inch vent pipe on the outdoor
furnace before filling with water to immediately
begin to protect the steel.
Fig. 47
Filling Outdoor Furnace and Purging Air
Using Pressurized Domestic Water
Backflow
Preventer
M
R
H
C
Valve #1
NOTE
Hot
Supply
Outdoor furnace water temp
setpoint should be set at
185˚F (85˚C) minimum.
Plenum
NOTE
Forced Air
Furnace
A pump must be installed in the hot
supply line between the outdoor furnace
and thermostatic valve.
Valve #4
Thermostatic
Valve
Valve #3
1" Central
PEX®
Bypass
Line
Water
Heater
Valve #5
Hot
Supply
Return Line
Valve #6
(Seasonal Manual
Bypass Valve)
Hose A
NOTE
Valve #2
NOTE: For illustration purposes only.
Actual configuration may vary.
Section 7 - Filling System with Water and Purging Air
Installer must comply with
all applicable codes and
regulations.
© 2015 Central Boiler
37
1. Connect the male end of garden hose A to valve #1
using the backflow preventer and two 3/4" female
hose x 3/4" male pipe adapters (p/n 4928). Connect
the female end of the garden hose to valve #2.
2. Close the valves on the hot supply and return lines
of the outdoor furnace.
3. Close valve #4 and valve #5.
4. Open valve #1 and valve #2. This step begins filling
the system with domestic water and purging the hot
supply line and thermostatic valve.
5. Remove cap from valve #3 and open valve #3
slightly to purge air from valve body. Close valve
#3 when air is purged.
6. Open valve #5.
7. Open the valve on the hot supply line of the outdoor
furnace for 5 minutes; then close the valve. Water
will purge air from the hot supply line. The valve
and attached fittings on the outdoor furnace will
become cold as water starts filling into outdoor
furnace.
NOTE: The valves on the hot supply and return
lines of the outdoor furnace, and valves #4 and
#5 should all be open, allowing the pump to
circulate heated water in the system. Start pump.
NOTE: If there are multiple circuits connected to
the outdoor furnace, repeat the process for each
circuit.
17.Refer to Firing the Outdoor Furnace to fire up the
outdoor furnace.
CAUTION
Be sure the outdoor furnace is filled with water
before firing. Water level is safe when the water
level indicator rod is above the vent cap (Fig. 48).
Corrosion Inhibitor Plus™ must be added before
the initial fill (see Water Quality and Maintenance).
Fig. 48
8. Close valve #5, #1 and #2.
9. Move hose A from valve #2 to valve #3.
10.Open valves #1, #3 and #4.
NOTE: Skip to Step 12 if your system does not
have a seasonal manual bypass valve (valve #6
shown in Fig. 35).
11.Valve #6 (seasonal manual bypass valve) should
be positioned to direct water through the heat
exchanger first.
12.Open the valve on the return line of the outdoor
furnace.
NOTE: Skip to Step 14 if your system does not
have a seasonal manual bypass valve (valve #6
shown in Fig. 35).
13.As soon as the valve on the return line of the outdoor
furnace is opened, turn valve #6 to the bypass
direction for 30 seconds; then turn valve #6 back to
previous position.
NOTE: The heat exchanger manifold (lower
manifold first) and fittings will become cold as
water flows through the heat exchanger to the
outdoor furnace.
14.Allow outdoor furnace to fill until the controller no
longer indicates
.
18.Check the system for leaks again. Inspect all
fittings and hose ends for any signs of leakage; repair
as necessary. It may be possible to stop a very slow
leak at a hose clamp by tightening the clamp after
the system has warmed up and the poly becomes
more pliable. It might also be necessary to install a
second hose clamp with the screw positioned on the
opposite side. Release the pressure upon completion
of the test.
NOTE: It should not be necessary to add water
to the outdoor furnace more frequently than
once every twelve months. If it is more frequent,
either there is a leak in the system or the outdoor
furnace is boiling because of improper operation
or maintenance (see Troubleshooting Section).
Be sure to locate and repair the problem
immediately. Frequently adding water can cause
deterioration in the water jacket. Each time water
is added, refer to Water Quality and Maintenance
for water testing procedures. If indicated by
test results, add Corrosion Inhibitor Plus™ as
required. Deterioration due to improper operation
and/or maintenance is not covered by warranty.
15.Close valves #1 and #3. Disconnect hose A and
replace caps on valves #1, #2 and #3.
16.Open the valve on the hot supply line of the outdoor
furnace and valve #5.
38
Section 7 - Filling System with Water and Purging Air
SECTION 8 – OPERATING INSTRUCTIONS
Fuel Quality and Storage
Wood pellets must be stored in a container or building
that prevents rain or other moisture from contact with
the fuel.
WARNING
Do not store fuel within the outdoor furnace
installation clearances or within the spaces
required for fueling, ash removal and other
routine maintenance operations.
NOTE: Fuel must not build up so that it prevents
the fuel door from closing as shown in Fig. 50. This
is an indication the burner auger is obstructed
or has quit turning. If this condition exists,
inspect the burner auger and clean or replace
as necessary. If condition persists contact your
Central Boiler dealer for more information.
Fig. 50
• Use only premium quality wood pellets.
• If fans are used in the fuel storage area, they should
be installed so as not to create negative pressures
in the non-habitable building where the outdoor
furnace is located.
Fuel Door
Blocked
Open
CAUTION
Do not burn plastic, garbage, treated wood or
fuels not listed for this outdoor furnace.
NOTE: Chloride or sulfurous gases will generate
if plastic or rubber is burned and will mix with
the moisture from the wood pellets to form
hydrochloric or sulfuric acids in the firebox,
creating corrosion.
NOTE: Wood pellets with a high sawdust
content may cause a feed rate interruption. An
interruption in fuel flow may result in an empty
burn chamber, or if the blockage frees itself after
the fire has gone out, a burn chamber full of
unburned fuel.
NOTE: Fuel must be flowing from the transfer
auger to the burner auger when the burner auger
is turning (see Fig. 49).
Fig. 49
Fuel Door Closed (fan off)
or
Fuel Door Open (fan on)
FireStar Controller
Refer to the FireStar Operation Manual for instructions
on how to use the FireStar controller.
Operating Precautions
NOTE: If the controller is flashing
the
system senses a low water condition. This
outdoor furnace is equipped with an automatic
shut down system if the water level falls to an
unsafe level. The water level in the outdoor
furnace is safe when the water level indicator rod
is above the vent cap (see Fig. 55).
1. Do not burn garbage, gasoline, rubber, engine
oil, naphtha, plastics, treated wood, cord wood or
combustibles other than the fuel specified.
2. Do not store combustibles within the installation
clearances listed on the Important Precautionary
Information page. Be sure to leave a safe amount
of room for cleaning out ash without causing a fire
hazard. Keep the area around the outdoor furnace
clear of combustible materials. Combustible
debris may be easily ignited if embers spill out of
the firebox.
3. The outdoor furnace water jacket must not be allowed
to pressurize. Inspect the vent cap periodically for
any obstructions or restrictions. The vent cap must
fit loosely over the vent (Fig. 51). Do not extend or
connect anything to the vent pipe.
© 2013 Central Boiler
Section 8 - Operating Instructions
39
Fig. 51
4. All cover plates, enclosures and guards must be
secured at all times except during maintenance,
inspection, and servicing.
5. In case of a power outage, a small generator can
provide enough electricity to operate the system.
6. If any questions should arise that cannot be answered
by the information in this manual, be sure to contact
either your dealer or qualified installer.
Filling the Hopper
Open the hopper lid (Fig. 52) and add wood pellets.
After filling, make sure the hopper lid is securely closed
to prevent moisture from entering the hopper. Do not
over-fill the hopper.
Fig. 52
Smoke in Hopper
How air flows through the furnace is an important
part of optimal operation. Smoke in the hopper is
an indication that the air flow through the furnace is
restricted, obstructed or different than it should be.
CAUTION
Operating for extended periods of time with air
flow through the furnace restricted (i.e., smoke
in the hopper) can damage components in the
furnace.
If smoke in the hopper occurs, check the following:
• Heat exchanger obstructed - clean the heat
exchanger (see Fig. 54).
• Aerator covered by ash - do not allow ash in
the burn chamber to accumulate over the aerator.
Use the cleaning rod to pull ash forward to ash
collection area.
• Carbon buildup - inspect the burner auger where
it enters the firebox for carbon buildup and clean
if necessary.
• Chimney is obstructed - inspect the chimney and
chimney connector and clean if dirty or obstructed.
If a spark arrestor is installed, ensure it is not dirty
or obstructed.
• Chimney too short - may need to increase the
height of the chimney.
Fig. 54
NOTE: The hopper lid may be locked to prevent
unauthorized access (Fig. 53).
Fig. 53
40
Section 8 - Operating Instructions
SECTION 9 – ROUTINE MAINTENANCE
PREVENTIVE MAINTENANCE SCHEDULE
S
on
E
as
SE
Se
st
Po
lly
ua
nn
-A
EC
mi
Se
TI
ly
nth
Mo
kly
ee
W
ON
ily
Da
OPERATION
SERVICE INTERVAL
n
tio
ra
pe
to n
irs so
e f ea
for of s
Be
Regular maintenance and inspections can
help extend the life of your outdoor furnace
and prevent high-cost repairs. This table is
meant to serve as a general guideline until
you become acquainted with how the outdoor
furnace operates with your specific application.
Check water level.
9.1
Remove ash.
C
Inspect firebox and firebox ash area.
9.2
B
9.3
Inspect gaskets.
9.4
Inspect and clean heat exchanger, chimney transition.
Inspect and clean aerator and burn chamber.
C
9.5
A
9.6
Lubricate door and hopper lid hinge points.
Check thermal valve.
9.7
B
9.9
Test thermal valve.
9.10
Check gas pressure, electrode.
9.11
Check pH and nitrite levels of water.
D
E
Check that the outdoor furnace is level.
F
Check fuel door operation.
9.8
A
When the outdoor furnace is new, daily for the first week.
B
When new, after one month, then midway through the heating season, and in the spring.
C
Weekly until interval for your application can be determined.
D
When new, after three months, then every six months thereafter.
E
Refer to Testing Treated Water in the Outdoor Furnace.
F
Refer to Leveling the Outdoor Furnace.
Section 9 - Routine Maintenance
41
CAUTION
Use only genuine Central Boiler Parts and
Accessories if it ever becomes necessary to
replace any component of the outdoor furnace.
ROUTINE MAINTENANCE
Routine inspections and maintenance are essential to the
proper operation and longevity of the outdoor furnace.
The items indicated in the preventive maintenance
schedule are intended to serve as a guideline. Actual
intervals between inspections and maintenance may
vary depending on a number of factors, including your
heat load requirements, type and quality of fuel used,
and outdoor temperatures.
1. Do not allow ash in the burn chamber to accumulate
over the aerator as shown in Fig. 56. Use the
cleaning rod provided to pull the ash forward to the
ash collection area.
Fig. 56
CAUTION
Turn off the FireStar controller before performing
any maintenance.
9.1 Water Level
The water level in the outdoor furnace is safe when
the water level indicator rod is above the vent cap (see
Fig. 55). If adding water is necessary, refer to the Water
Quality and Maintenance section.
Fig. 55
2. It is important to remove the ash in the firebox
before it solidifies to prevent sealing in moisture
on the bottom and along the edges. It is especially
important to scrape all of the firebox where build up
and ash are collected. Any heavy or solidified ash
should be removed.
NOTE: If these maintenance operations are not
performed as directed, deterioration can result
from the moisture trapped between the ash and
the steel.
3. If burning wood pellets with a high ash content, a
hard deposit may form in the burn chamber. Remove
the deposit by scraping the burn chamber with the
cleaning rod provided.
9.2 Ash Removal
An ash scoop is included with your outdoor furnace. For
your protection, always wear the appropriate personal
protective gear when cleaning ash from the firebox.
CAUTION
Always wear the appropriate personal protective
gear when cleaning ash from the firebox.
CAUTION
When cleaning the outdoor furnace, be
careful not to spill any hot ash outside of the
noncombustible container.
42
4. Disposal of ash - Place ash in a metal container with
a tight-fitting lid. Store the closed container of ash
on a noncombustible surface, well away from all
combustible materials until ready for final disposal.
Do not dispose (either by burying or other means)
until all cinders have thoroughly cooled.
5.Each time the ash are cleaned out, inspect the
outdoor furnace door rope gasket to make sure it is
sealing properly (see Fig. 58).
9.3 Firebox
NOTE: Proper firebox maintenance is essential
to the longevity of the outdoor furnace.
Remove ash as described in Ash Removal section.
Scrape all surfaces in the firebox, paying close attention
to the corners (see Fig. 57). If needed, the aerator and
burn chamber can be removed for a more thorough
cleaning (see Aerator and Burn Chamber).
Section 9 - Routine Maintenance
Fig. 57
9.4 Gaskets
Fig. 58
9.5 Heat Exchangers and Chimney
Transition
The heat exchangers should be cleaned every time ash
is removed, or if air flow through the heat exchangers
becomes restricted (see Fig. 60).
To inspect the heat exchangers, remove the chimney
transition cover on the back of the furnace and open
the firebox door. It will probably be necessary to kneel
down at the back of the furnace to look through each
heat exchanger passageway. The heat exchangers
taper up from the back of the furnace to the front. Pay
particular attention to the top of each passageway as
this is where ash tends to accumulate. The top of each
heat exchanger passageway is where most air flow and
heat transfer occur, so it is especially important to keep
the top free of any buildup.
Fig. 60
Inspect the rope gasket on the furnace door and on the
chimney transition cover at the back of the furnace. A
uniform indentation in the rope indicates the rope gasket
is sealing properly. If it is not sealing properly, or if the
rope gasket is damaged, replace the rope gasket.
Using Fig. 59 as a reference, inspect the hopper lid
gasket and replace if necessary.
NOTE: Replacement gaskets for the furnace
door, chimney transition cover and hopper are
available from authorized Central Boiler dealers.
Fig. 59
Remove deposits by scraping with the cleaning rod
provided with your outdoor furnace. Use the cleaning
rod from both the front and the back of the furnace,
working from top to bottom of each passageway in the
heat exchanger.
Inspect the chimney transition and clean if an excessive
amount of buildup is present.
NOTE: Twice a month during the heating season,
inspect the chimney transition for excessive
buildup. If present, the buildup should be
removed for proper operation and fire safety. In
case of a chimney fire, close the firebox door.
Check the integrity of the chimney transition attachment
bolts (Fig. 61) as they support the weight of the chimney.
Section 9 - Routine Maintenance
43
Fig. 61
Fig. 63
9.6 Aerator and Burn Chamber
As the quality of wood pellets varies from region
to region, so will the requirements for component
maintenance. The aerator and burn chamber should be
inspected on a regular basis to ensure mineral deposits
do not hinder burner performance. Regular inspection
and removal of any deposits will ensure best furnace
operation.
NOTE: Make it a habit to visually inspect the
burner on a weekly basis during the heating
season.
Fig. 62
2. To clean combustion air holes, use a suitably sized
drill bit, round wire brush or other suitable tool to
remove any deposits. Be careful not to damage,
deform or increase the size of the combustion air
holes. Clean ash from inside the burn chamber.
CAUTION
Ignitor
Do not strike the aerator or burn chamber with a
hammer or other hard item to remove deposits.
Doing so could damage the parts and prevent
proper operation of the burner.
CAUTION
Burn Chamber
© 2014 Central Boiler
CAUTION
Before performing any maintenance on the burn
chamber or aerator, shut off the burner, allow the
outdoor furnace to cool and clean the firebox.
Disassembly
1. Turn the aerator 1/4 turn counterclockwise and pull
straight forward to remove.
2. Remove the side access panel from the furnace. Roll
back the insulating tape securing the thermocouple
and remove the thermocouple.
3. Open the firebox door. Using Fig. 63 as a reference,
place a 3/4" thick, 4-ft long board under the front of
the burn chamber. Use the board to pry up the front
of the burn chamber; then push the board in until
it reaches the back of the firebox. Pry up the entire
burn chamber to disengage the hooks on the back
of the burn chamber. Remove the board with burn
chamber through the door.
44
Inspecting and Cleaning
1. Inspect the aerator and burn chamber for any buildup of mineral deposits, especially in and around the
combustion air holes.
3. Scrape carbon deposits from the auger, the surfaces
of the aerator and the burn chamber.
Maxim M255 PE models
Aerator
NOTE: It will be necessary to angle the burn
chamber when removing it through the firebox
opening.
Before placing the aerator in water, allow it to
cool thoroughly. Do not put the aerator in snow
to cool faster as the aerator can be damaged.
4. Inspect gas ignitor.
Assembly
1. Inspect the burn chamber gasket for damage and
replace if necessary. Place the 3/4" thick, 4-ft long
board used to remove the burn chamber in the
firebox opening; then place the burn chamber on top
of the board.
NOTE: It will be necessary to angle the burn
chamber to install it through the firebox opening.
2. Push the board and burn chamber to the back of the
firebox; then use the board to lift the burn chamber
up so the hooks on the back of the burn chamber can
engage. Remove the board.
3. Place the aerator on the end of the auger tube; then
rotate it 1/4 turn clockwise to lock it in position.
Section 9 - Routine Maintenance
4. Install the thermocouple and replace the insulating
tape. Install the side access panel on the back of the
outdoor furnace.
9.7 Door and Hopper
Lubricate the door pivot points and hopper lid latch
with a light petroleum distillate (WD-40 or equivalent).
9.8 Check Fuel Door Operation
Make sure the fuel door is open when the combustion
fan is running and closed when the fan is stopped. It is
important to check the fuel door monthly to make sure
it is operating properly. When operating properly, the
fuel door will be closed when the combustion fan is not
operating.
9.9 Thermal Valve
The thermal valve does not require electricity to operate.
If during a power outage, a high temperature condition
is detected in the burner auger area, the thermal valve
is designed to release a small amount of water into the
burner auger area to cool the area.
Twice each heating season, check to see if the thermal
valve has activated:
1. Disconnect the electrical power at the main power
source.
2. Remove the access panels from the back corner of
the furnace and set aside.
3. Remove the 1/2" silicone tubing from the thermal
valve, leaving it attached to the discharge tube.
Blow air through the tubing to clean. Connect the
silicone tubing to the thermal valve making sure not
to kink the silicone tubing.
NOTE: Fig. 64 shows one possible configuration
for a thermal valve. Installations may vary
slightly.
4. Install the access panels.
5. Connect the electrical power at the main power
source.
CAUTION
Do NOT operate this appliance with any panels
removed.
IF THE THERMAL VALVE ACTIVATES
If the thermal valve activates, it will be necessary to
clean out the areas in which water from the thermal valve
may have come in contact with the wood pellets. Do not
use the furnace until these areas have been thoroughly
cleaned. Read and understand these instructions before
beginning the procedure.
NOTE: Fig. 64 illustrates the disassembly
required to clean the furnace if the thermal valve
activates.
1. Disconnect the electrical power at the main power
source.
Fig. 64
Transfer Auger
Inspection
Window
Discharge
Tube
NOTE
Illustration shows one
possible configuration for
thermal valve.
Installations may vary.
Burner Auger
Motor
Snap Disc
Burner
Auger
Shaft
Key
Red Cap
Thermal
Valve
(Insulated)
Motor
Mount Plate
© 2013 Central Boiler
Section 9 - Routine Maintenance
45
2. Remove the access panels from the back corner of
the furnace and set aside.
3. If a one-pound propane cylinder is threaded onto the
regulator on the gas valve, remove it. Otherwise turn
off the gas supply at the appliance service valve.
4. Open the hopper lid and empty the hopper. One
option for emptying the hopper is to use a wet-dry
shop vacuum to remove the unused wood pellets.
Wood pellets at the bottom of the hopper may have
been saturated with water causing them to expand
and fill the opening. If it is necessary to use a tool
to break up the expanded wood pellets, use extreme
caution not to damage any components of the
furnace.
Remove Transfer Auger
1. Disconnect the wires from the transfer auger motor.
2. Remove the bolts securing the transfer auger motor
mount plate to transfer auger housing; then remove
the transfer auger assembly.
NOTE: Do not pull straight out or force the
transfer auger assembly while removing. Turn
the assembly counterclockwise.
3. Remove the screws securing the inspection window
to the side of the hopper; then remove the inspection
window.
4. Remove the 1/2" silicone tubing from the thermal
valve, leaving it attached to the discharge tube. Blow
air through the tubing to clean.
Remove Aerator, Burner Auger and Burner
Auger Motor
1. Inside the firebox, turn the aerator 1/4 turn
counterclockwise and pull straight forward to
remove.
2. Disconnect the burner auger motor wiring connector.
3. Remove the bolt and washer securing the burner
auger to the burner motor. Set the bolt and washer
aside for assembly.
4. Remove the four bolts securing the motor mount
plate to the transition box; then remove the burner
auger motor and motor mount plate.
NOTE: On M255 P models, the motor mount
plate is installed behind the gas valve mounting
bracket.
5. Remove the key from the keyway slot on the auger
shaft and set aside for assembly.
Clean the Affected Areas
1. Inspect the bottom of the hopper and remove any
wet fuel from the opening at the bottom.
2. Using a wet-dry shop vacuum, clean the transfer
auger tube and the drop tube of any unused fuel or
wet fuel; then clean the transition box that houses
the burner assembly.
NOTE: Make sure that no fuel gets pushed
back toward the combustion fan area or the
combustion fan could be damaged.
3. Make sure the flightings on the augers are clean and
dry.
Replace Snap Disc
1. Disconnect the two wires from the snap disc located
on top of the transition box.
2. Remove the two screws securing the snap disc to the
transition box; then remove the snap disc.
3. Place a new snap disc into place and secure with
screws; then connect the two wires.
Install Burner Auger, Burner Auger Motor
and Aerator
1. Apply grease to the portion of the burner auger shaft
that will be seated in the bushing; then, from inside
the firebox, install the burner auger into the burner
assembly making sure it is properly aligned and
seated in the bushing.
2. Install the motor mount plate with burner motor
behind the gas valve mounting bracket on the
transition box. Tighten the screws hand-tight only.
3. Align the keyway slot on the auger shaft with the
keyway slot in the burner motor; then tap the key
into the slot. Secure the burner auger with the bolt
and washer removed earlier. Tighten securely.
4. Using a flashlight inside the firebox, check that the
auger flightings are centered in the burner tube. If
necessary, loosen the motor mount plate bolts and
move the motor mount plate to center the auger
flightings in the burner tube. Tighten the motor
mount plate bolts securely.
Install Transfer Auger
1. Install the transfer auger assembly in the transfer
auger housing (see Fig. 64). Make sure the end of
the transfer auger tube fits over the brass guide in the
transfer auger housing. Verify by visually checking
from the top of the hopper (see Fig. 65). Secure with
the bolts.
6. Using a wooden block, tap the burner auger into the
firebox. Do not hit the bushing.
7. Remove the burner auger from inside the firebox.
46
Section 9 - Routine Maintenance
Top View of Maxim Hopper
4. Push down on the red cap of the thermal valve and
run a small amount of water through the valve to
make sure it is operating properly.
Transfer
Auger
5. Connect the silicone tubing to the thermal valve
making sure not to kink the silicone tubing.
Fig. 65
6. Install the access panels.
7. Connect the electrical power to the main power
source.
Brass Guide
2. Connect the wires to the transfer auger motor.
Finish Installation
1. Install the inspection window and secure with the
screws.
2. Attach the 1/2" silicone tubing to the thermal valve
and secure with hose clamp.
3. Install the access panels.
4. Connect the electrical power at the main power
source.
5. If a one-pound propane cylinder was installed, thread
it onto the regulator on the gas valve. Otherwise turn
on the gas supply at the appliance service valve.
6. Before adding fuel to the hopper, start the furnace
and verify that both augers are turning freely without
binding. The transfer auger can be viewed from the
hopper and the burner auger can be viewed using a
flashlight from inside the firebox.
9.11 Gas Ignitor - M255 P Models
NOTE: Any maintenance on the gas ignitor should
be done by a qualified installer in accordance
with applicable codes.
Gas Pressure
Pressures should be checked while burner is operating.
Gas pressure can be tested using the gas pressure taps
on the gas valve. Ensure that the inlet side (supply)
gas pressure is no less than 10 inches of water column.
Outlet side (manifold) gas pressure must be no less than
9 inches of water column.
If the supply gas pressure is correct and the manifold
gas pressure is not, the manifold gas pressure can be
adjusted by removing the cap on the gas valve and
turning the adjustment screw with a flat screwdriver (Fig.
66). Turning the adjustment screw clockwise increases
manifold gas pressure; turning it counterclockwise
decreases manifold gas pressure.
Fig. 66
7. Once it has been determined the augers are turning
freely, add fuel to the hopper and start the furnace
following the procedure in Initial Start-up.
9.10 Test Thermal Valve
Twice each heating season (at the beginning and the
end), check to make sure the thermal valve operates
properly.
Electrode
1. Disconnect the gas line and spark plug wire; then
remove the two 5/16" screws securing the burner
tube assembly and remove the burner tube assembly.
WARNING
2. The electrode must be adjusted properly to provide
the proper spark and sense the flame when lit. The
electrode rod must be centered in the end of the
burner tube (Fig. 67).
Allow the outdoor furnace to thoroughly cool
down before performing maintenance.
1. Disconnect the electrical power at the main power
source.
2. Remove the access panels from the back corner of
the furnace and set aside.
3. Remove the 1/2" silicone tubing from the thermal
valve; then place a small cup under the outlet on the
valve.
Section 9 - Routine Maintenance
47
WATER QUALITY AND MAINTENANCE
An important part of outdoor furnace maintenance
is controlling the quality of the water in the furnace.
Central Boiler supplies a pH test strip and a nitrite test
kit with each new outdoor furnace.
Fig. 67
3.Whenever the burn chamber is removed for
maintenance, or if there is a problem with the gas
ignition, clean the electrode using a coarse (i.e.,
denim) cloth rag. If there is excessive creosote or
deposits on the electrode that are difficult to remove,
oven cleaner may be used to soften the deposits.
Inspect for cracked insulation, damage or for any
loose components.
4. Make sure the connector on the end of the ignitor is
threaded on tightly.
5. When properly adjusted, the electrode will appear
in the end of the burner tube as it does in Fig. 68.
Fig. 68
Electrode
M250_ELECTRODE
Water Test Kits and Test Results
It is very important to keep record of water test results
(include the date, pH and nitrite level). If subsequent
water tests indicate a pH that is too low and/or a nitrite
level that is too high, the results should be verified using
a new test kit.
The pH test strips and Permanganate Reagent each have
a varying shelf life that can affect their accuracy. Test
kits should be stored in a dry area at room temperature
to obtain maximum accuracy over a longer period of
time.
NOTE: Do not store the test kit where it will be
exposed to heat (e.g., on top of the water heater).
The pH of the water in the outdoor furnace will not
decrease unless fresh water is added to the furnace. The
nitrite level of the water in the furnace will not increase
unless Corrosion Inhibitor Plus™ is added.
For example, if a water test in the fall of the year indicates
a pH of 8.5 and a nitrite level of 20 drops by nitrite test
(2000 ppm) and no water or Corrosion Inhibitor Plus™
is added, a water test the following spring must indicate
a pH of at least 8.5 and a nitrite level of no more than 20
drops by nitrite test (or slightly less, due to evaporation).
If the test indicates a significantly lower pH level or
higher nitrite level, perform another test with a new test
kit to verify the results. If the results are +10% different
using a new test kit, either water or Corrosion Inhibitor
Plus™ has been added to the system.
If a test is conducted and verified that indicates a high
pH (above 9.5) and/or nitrite level (above 30 drops),
DO NOT ADD MORE CORROSION INHIBITOR
PLUS™. Adding Corrosion Inhibitor Plus™ increases
nitrite and pH levels. The outdoor furnace should be
drained until the LED display flashes
to indicate
that the water level is below the sensor; then add fresh
water until the water level indicator rod is above the
vent cap (Fig. 55). Circulate the water for 24 hours and
test the water again.
Testing Supply Water
Before filling the outdoor furnace with water, test a
sample of the supply water that will be used to fill the
outdoor furnace (softened water is recommended).
1. Collect a small sample of the water to be used to fill
the outdoor furnace in a clean container.
2. Dip the pH test strip from the test kit in the water
sample. Shake excess water off the test strip.
Compare the color of the test strip to the chart
provided to determine pH level.
48
Section 9 - Routine Maintenance
3. If the pH level is between 6.5 and 8 and there are
no other known water quality problems, then the
outdoor furnace may be filled with this water.
Fig. 70
4. If the water to be used to fill the outdoor furnace has
a pH level of less than 6.5 or greater than 8, a sample
of the water should be sent to a water quality test
lab for recommended treatment, the water should
be conditioned, or water should be supplied from a
different source.
Corrosion Inhibitor Plus™ and Initial
Treatment
Central Boiler Corrosion Inhibitor Plus™ (p/n 1650)
gives optimum protection when it is used to initially
treat the water and is then maintained at proper levels.
The initial nitrite level target is 20 drops by nitrite
test, but 20 to 30 drops is acceptable. Do not exceed
treatment of higher than 30 drops by nitrite test.
Before collecting the sample, drain about a quart (liter)
The recommended initial treatment rate for the outdoor of water; then carefully fill the sample container without
furnace is specified by units. One unit of the Corrosion contaminating the sample. Be sure to properly close
Inhibitor Plus™ is a 1-gallon (3.78-liter) container. The the valve when finished.
normal rate for the initial treatment is 1/2 of a unit.
Testing Treated Water in the Outdoor
NOTE: If the system has a larger than normal Furnace
water capacity, more Corrosion Inhibitor Plus™ 1. If no antifreeze is present in the water, use Test Kit
(p/n 405). If antifreeze has been added to the water,
should be added at a recommended amount of
one unit per 180 gallons (680 liters) of water.
use Test Kit (p/n 597).
Refer to Section 7 - Filling System with Water and 2. Dip the pH test strip from the test kit in the water
Purging Air for the recommended initial treatment of
sample. Shake excess water off the test strip.
Corrosion Inhibitor Plus™.
Compare the color of the test strip to the chart
provided to determine pH level. The pH of the water
Obtaining Treated Water Sample
should now be between 8.0 and 9.5.
A treated water sample from the outdoor furnace can be
obtained either from the valve on the hot water heater 3. Rinse and fill the sample tube to the 25 mL mark
(Fig. 69) or from the furnace drain valve (Fig. 70).
with treated water from the outdoor furnace.
Fig. 69
4. Add 25 drops of Sulfuric Acid (p/n 404) to the water
sample and swirl to mix.
WARNING
Valve can be used
to obtain sample of
treated water from
furnace.
Sulfuric Acid is a corrosive acid. Handle carefully.
Carefully read and follow precautions on test
chemical labels. Keep test chemicals away from
children. Safely dispose of tested samples.
5.Using the dropper, add Permanganate Reagent
(p/n 403) one drop at a time, swirling the water and
counting each drop, until the color changes from
colorless to pink that persists for at least one minute.
NOTE: Always hold the dropper in a vertical
position to ensure proper droplet size.
6. If the nitrite level is not at least 20 drops by nitrite
test, add 1/4 unit of Corrosion Inhibitor Plus™ (p/n
1650); then circulate water for 24 hours and repeat
procedure, as needed, to achieve a nitrite level of at
least 20 drops by nitrite test.
Section 9 - Routine Maintenance
49
7. Do not exceed treatment of higher than 30 drops
by the nitrite test. If the test requires more than 30
drops, dilute the water by draining water from the
system until the LED display flashes
. Then
add fresh water until the water level indicator rod is
above the vent cap (Fig. 55). Start the pump(s) and
circulate water for 24 hours. Recheck nitrite levels.
8. After the proper nitrite level has been obtained,
check pH to make sure it is between 8 and 9.5.
After initial treatment, the maintenance nitrite level
target is 15 drops by nitrite test, but 15 to 30 drops is
acceptable. One drop of permanganate reagent equals
approximately 100 ppm.
System Maintenance
The pH and nitrite levels of the water, once treated,
should remain stable as long as water is not added to
the outdoor furnace. If water is added to the outdoor
furnace and/or system, the system water should be
tested and Corrosion Inhibitor Plus™ should be added
(if necessary) to maintain the recommended level of
protection.
NOTE: If there is a leak in the system or if the
outdoor furnace loses water from boiling
frequently, the problem should be identified and
repaired immediately. Under normal operation,
little or no water needs to be added. Adding water
to the outdoor furnace may cause corrosion if
not immediately treated with Corrosion Inhibitor
Plus™ to the proper pH and nitrite levels. In
addition, the amount of dissolved solids in the
system (due to adding additional water) can
cause problems.
After the initial three months of operation and every
six months thereafter, the pH and nitrite levels of the
system water should be tested. These levels should be
maintained as previously stated.
POST HEATING SEASON MAINTENANCE
The water should be left in the outdoor furnace
during the non-heating season. Check pH and nitrite
levels as described in the Water Quality and Maintenance
section; add Corrosion Inhibitor Plus™ (p/n 1650) as
needed. If Corrosion Inhibitor Plus™ is added, run the
circulation pump for two days to thoroughly mix in the
new corrosion inhibitor. If water is added, bring the
water up to operating temperature as soon as possible.
If water is added more frequently than once during the
heating season, a complete inspection of the outdoor
furnace and plumbing should be performed.
2. Remove the aerator and burn chamber; inspect and
clean as explained in section 9.7 Aerator and Burn
Chamber.
3. Clean all the ash out of the outdoor furnace. Scrape
the walls and floor of the firebox.
4. Check the chimney box and flues. Clean out any
excessive buildup. Any large or dry crusty deposits
on the walls or heat exchanger area should be
removed. When cleaning the firebox, be sure to wear
the appropriate personal protective gear.
CAUTION
To minimize corrosion caused by accumulated
ash, it is especially important to clean the
chimney, chimney box and flues at the end of the
heating season.
5. When the outdoor furnace is clean, carefully inspect
the firebox for any signs of excessive corrosion
or deterioration. If any corrosion or deterioration
is found, call your dealer. It is always better to do
maintenance during the non-heating season.
6. After the inspection is completed, apply a thin coat
of new motor oil to the firebox and heat exchanger
being sure to work oil into all corners.
7. Inspect the thermal valve as explained in section 9.9
Thermal Valve.
8. Place a cover over the chimney to keep rain from
entering the outdoor furnace.
9. If the water is left in the outdoor furnace during
the non-heating season, condensation can occur
in the firebox. Periodically during the non-heating
season, check for condensation in the firebox. To
prevent condensation in the firebox, one option is
to keep a 60W light bulb on in the firebox during
the non-heating season. Another option is to keep a
circulating pump running.
1. At the end of the heating season, clean all of the fuel
from the hopper. Clean the fuel from the augers by
pressing the Auger button until no fuel enters the
burn chamber.
50
Section 9 - Routine Maintenance
SECTION 10 – TROUBLESHOOTING
A. FURNACE DOES NOT HEAT (BUILDING IS
LOSING TEMPERATURE)
1. Out of fuel - Check firebox to see if fire is out. Add
wood pellets as necessary.
2. Fire out - If the controller is flashing
refer
to FireStar Controller for Maxim Operating
Instructions.
3. Thermal valve opened - If during a power outage,
a high temperature situation is detected in the burner
auger area, the thermal valve will open to release a
small amount of water into the burner auger area
to cool the area. To determine if this has happened,
first look in the firebox for the presence of water.
Also check the glass inspection port just above the
burner auger. If the pellets appear to have expanded
from absorbing water, the thermal valve has opened.
Contact your Central Boiler dealer for assistance.
4. Circulation valve(s) closed - Be sure all valves in
the system are open.
5. Circuit breaker off - Reset the circuit breaker that
supplies power to the outdoor furnace.
6. Circulation pump(s) not operating - Disconnect
power to the pump. Close valves at the pump.
Disassemble the pump and try to turn the pump shaft.
If the shaft is stuck, replace the pump cartridge.
Replace only the cartridge whenever possible. If
necessary, replace the pump. Follow instructions
supplied with the pump.
7. Air in system - Check for air in the supply and
return lines or heat exchangers. If you hear a
gurgling sound in a heat exchanger, air is present in
the system. Shut off the pump, wait 15 seconds and
start the pump. If it is necessary to force air from
lines, refer to Section 7.
8. Outdoor furnace exhaust obstructed - Check
outdoor furnace exhaust for obstructions by
removing the chimney transition cover to expose
the heat exchanger. The heat exchanger can also be
observed from the front of the furnace through the
front door opening.
9. Combustion fan blocked or obstructed - Check
the combustion fan for obstructions.
10.Building(s) poorly insulated or uninsulated Poorly insulated or uninsulated buildings and/
or buildings with uninsulated or poorly insulated
ceilings can cause excessive fuel consumption and
or heating problems.
Section 10 - Troubleshooting
11.Supply and return lines installed incorrectly Make sure the hot supply water line is connected to
the correct fitting on the outdoor furnace and heat
exchanger.
12.Circulation pump(s) installed incorrectly Circulation pump(s) must be installed in the supply
line(s) with the arrow on each pump pointed away
from the outdoor furnace. Remove the pump and
install correctly. Refer to the System Installation
section for installation guidelines.
13.Underground supply and return lines insulated
poorly - Heat loss from poorly insulated underground
supply and return lines is often indicated by an
unusually high amount of snow melting above the
lines when the ground temperature is 10ºF (-12˚C)
or colder.
14.Supply and return lines uninsulated - Uninsulated
supply and return lines in areas that are not intended
to be heated (unheated crawl spaces, under mobile
homes, etc.) may cause excessive heat loss. Insulate
the supply and return lines.
15.Low water - If the controller is flashing
the
system senses a low water condition. Check water
level and if necessary add water according to the
Water Quality and Maintenance section. If adding
water does not correct the problem, contact your
Central Boiler dealer.
16.Poor water quality - Water with high amounts of
solids, sand or dirt can create deposits inside the
wall of heat exchanger components, reducing the
amount of heat output. If this condition is suspected,
contact your Central Boiler dealer.
17.Propane tank too cold - Extremely cold
temperatures (-40˚F/-40˚C) can prevent propane
from vaporizing properly. A one-pound propane
tank will stay warmer if installed on the regulator
inside the rear access area. The propane burner is
not a backup heat source.
B. FURNACE IS OVERHEATING (FIRESTAR
)
LED DISPLAYS
1. FireStar controller set incorrectly - Lower the
water temperature setpoint and/or adjust the heat
output settings in one or all of the three modes (see
Setting the FireStar Controller for Heat Load and
Efficiency).
2. High limit switch tripped - Lower the water
temperature setpoint and/or adjust the heat output
settings in one or all of the three modes (see
Setting the FireStar Controller for Heat Load and
Efficiency).
51
3. Water is not circulating - The pump should run
and water should circulate continuously through the
supply and return lines to keep water temperature
uniform in the outdoor furnace.
4. Circulation valve(s) closed - Be sure the proper
valves in the system are open to allow circulation.
C. BACK BURN (FIRESTAR DISPLAYS
)
1. High temperature in burner auger area Everything but the burner auger will be disabled.
The burner auger will run for two minutes, pause
for 10 minutes, and continue as required. The Back
Burn alarm will not stop until the controller detects
that the temperature in the burner auger area has
dropped.
D. FREQUENT PUMP TROUBLE OR POOR
WATER CIRCULATION
1. Pump mounted incorrectly - The pump must be
mounted with the pump motor horizontal and the
junction box either on the side or on top (see Fig.
71).
Fig. 71
E. BURNING AN EXCESSIVE AMOUNT OF
FUEL.
1. High volume water heating - High volume water
heating (e.g., car wash, swimming pool, etc.) will
require high fuel consumption.
2. Excessive heat loss - See items 8-12 of Furnace
Does Not Heat.
3. Supply and return line heat loss - If not using
ThermoPEX, supply and return lines buried in a
wet, low-lying area may cause a large heat loss that
will greatly increase the fuel consumption.
4. High heat demand - Concrete slabs (with radiant
heat) that are poorly insulated or are exposed to
water or cold outside temperatures will require
increased fuel consumption. Bringing a concrete
slab up to temperature the first time will take a
considerable amount of time and fuel; once warm,
fuel consumption will be reduced if the concrete
slab and building are insulated properly. The
following items will cause a high heat demand: poor
insulation, large amounts of glass windows/doors
(e.g., greenhouses), overhead doors, uninsulated
crawl spaces, outdoor air infiltration and air leaking
through foundation.
F. FUEL NOT BURNING PROPERLY
1. Poor fuel or out of fuel - See Fuel Quality and
Storage section for recommendations about fuel
types. Check firebox to see if fire is out. Add wood
pellets as necessary.
2. Combustion fan blocked or obstructed - Check the
combustion fan and air flow path for obstructions.
2. Deposits in water lines/heat exchanger walls - If
water high in silica or other mineral content has
been used to fill the outdoor furnace, material
deposits may build up on the insides of the supply
and return lines and on the heat exchanger walls. If
this occurs, the system will need to be drained and
then cleaned using Sludge Conditioner (p/n 166).
The system must then be refilled with the proper
amount of Corrosion Inhibitor Plus™ (p/n 1650)
and good quality water (softened water, if possible).
3. Outdoor furnace exhaust obstructed - Check
outdoor furnace exhaust for obstructions. To inspect
the heat exchangers, remove the chimney transition
cover on the back of the furnace and open the firebox
door. It will probably be necessary to kneel down at
the back of the furnace to look through each heat
exchanger passageway.
3. Water will not circulate - If the system has been
drained and refilled, or if the system has been
opened for any reason (e.g., replacement of pump,
adding heat exchangers, repairing a leak), air must
be purged from the system (see Filling System with
Water and Purging Air section).
4. Poor water quality - Water with high amounts of
solids, sand or dirt can cause frequent pump failure.
Use softened and/or filtered water.
52
Section 10 - Troubleshooting
Fig. 72
H. IF CORROSION IS PRESENT
Corrosion in the firebox can occur when the outdoor
furnace is being operated improperly. To maximize the
life of your investment, it is important to identify signs
of corrosion early (you can do this by performing the
items in the Preventive Maintenance Schedule) and
take measures to correct it as soon as possible. Some,
but not all, causes of corrosion are listed below with
possible solutions. If you are unsure how to proceed,
contact your Central Boiler dealer.
1. Water temperature is too low - If the heat load in
the system is too large, the water in the system will
not reach high enough temperatures and corrosion
can occur. Re-evaluate the system and match heat
load to the outdoor furnace.
NOTE: To reduce condensation in the firebox,
set the temperature to 185˚F or higher.
2. Heat load is too high - Reduce heat load.
3. Thermostatic valve is not installed - A thermostatic
valve must be installed on each set of supply and
return lines in the system to maintain the outdoor
furnace water temperature above 150˚F (65˚C).
4. Heat output set too high or too low - For best
results, determine the lowest water temperature
setpoint the outdoor furnace can be set to that will
supply enough heat to the heat emitters. See FireStar
Controller Manual for more information.
5. Air setting too high or too low - See Setting the
FireStar Controller for Heat Load and Efficiency.
G. BURNER AUGER MOTOR NOT TURNING
1. Wood pellets wet or swollen - Check to see if
the wood pellets have absorbed moisture and may
be swollen in the burner auger area. If the thermal
valve has activated, it will be necessary to remove
all of the pellets from the hopper; then remove the
transfer auger, aerator, burner auger and burner
auger motor and clean the entire area.
2. Burn chamber obstructed - Clean the burn
chamber especially at the end of the auger.
3. Motor overheated - Clean the burner auger and
allow the burner auger motor to cool.
Section 10 - Troubleshooting
4. Firebox wasn't cleaned out at the end of the
heating season - Be sure to follow the post-heating
season maintenance schedule which includes
scraping out firebox and removing all ash.
J. WATER TEMPERATURE AT SUPPLY PORT
LOWER THAN THE FIRESTAR INDICATES
1. Water flow too low - Add wraparound pump if
using one set of lines. Install higher pressurevolume pumps if using two sets of lines.
K. LOW WATER (FIRESTAR LED DISPLAYS
)
System leak - Try to identify the leak by inspecting all
lines, fittings, heat exchangers, etc. in the system and
repair as needed. If the leak cannot be found and if there
is no chance of the system or furnace freezing, the
following procedures can help determine whether the
leak is in the furnace or somewhere else in the system:
a. Turn off the FireStar controller; then completely
empty the firebox of all coals, embers and ash.
b. Allow the furnace to cool below 100˚F (38˚C).
c. Refill the outdoor furnace with water until the
water level indicator rod is above the vent cap. Add
Corrosion Inhibitor Plus™ if needed.
d. Record the water level by measuring how far the
water level indicator rod is above the vent cap.
e. Close all shut-off valves on the hot supply and
return lines at the outdoor furnace.
53
f. Check the water level periodically during the next
48 hours (the water level may drop slightly as the
water cools).
g. Inspect the firebox and under and around the outside
of the outdoor furnace for evidence of a leak each
time the water level is checked.
During the 48-hour inspection period, the water lines
should also be checked for leaks using a pressure gauge
and the following procedure:
a. Isolate the furnace by closing all shut-off valves on
the hot supply and return lines at the furnace.
WARNING
Be sure to close all shut-off valves on the hot
supply and return lines at the furnace. DO NOT
ALLOW THE FURNACE TO PRESSURIZE.
b. Isolate each zone in the system using shut-off valves.
c. Pressurize each zone with domestic water or air;
then check the pressure gauge after 12 hours. A drop
in pressure indicates that a leak is present in the
zone. Before resuming furnace operation, it will be
necessary to repair the leak.
L. SMOKE IN THE HOPPER
How air flows through the furnace is an important part of
optimal operation. Smoke in the hopper is an indication
that the air flow through the furnace is restricted,
obstructed or different than it should be.
CAUTION
Operating for extended periods of time with air
flow through the furnace restricted (i.e., smoke
in the hopper) can damage components in the
furnace.
5. Chimney dirty or obstructed - Inspect the
chimney transition and chimney for obstructions or
restrictions and clean if necessary.
6. Spark arrestor (if present) dirty or obstructed Inspect the spark arrestor screen for obstructions and
remove. Clean the spark arrestor if it is restricting air
flow.
7. Chimney not drafting properly - Proper draft is
necessary for the Maxim to operate optimally. Draft
occurs when the temperature in the chimney is high
enough to cause a negative pressure that "pulls" the
exhaust up through the heat exchanger and out the
chimney.
If poor draft is suspected, check that the chimney
transition cover is properly sealing. Adding chimney
sections may be required. However, due to a number
of variables (e.g., objects like buildings and trees in
close proximity, nearby terrain such as hills, valleys,
etc.), poor draft can be an intermittent problem.
M.CREOSOTE ON COMBUSTION FAN
1. Outdoor furnace not level - The furnace should be
leveled so that the back of the transition box (i.e., the
burner auger motor end) is slightly higher than the
front. If the burner auger is not sloped down toward
the front of the furnace, condensation can form in
the burner auger tube and drip into the transition
box. See Leveling the Outdoor Furnace section.
2. Ash covering aerator - Do not allow ash in the burn
chamber to accumulate over the aerator.
Fig. 73
1. Heat exchanger dirty or obstructed - Because the
gases moving through the heat exchanger are hot,
most of the heat transfer occurs at the top of the heat
exchangers. It is therefore important to ensure that
the top of each heat exchanger passageway is clean
and not obstructed or blocked from ash. Use the
procedure from 9.5 Heat Exchanger in the Routine
Maintnenace section to inspect the heat exchanger
for obstructions or restrictions and clean if necessary.
2. Aerator covered by ash - do not allow ash in the
burn chamber to accumulate over the aerator. Use
the cleaning rod to pull ash forward to ash collection
area.
3. Carbon buildup - inspect the burner auger where
it enters the firebox for carbon buildup and clean if
necessary.
4. Fan setting for HIGH mode set too high - Decrease
the fan setting for HIGH mode (see Setting the
FireStar Controller for Heat Load and Efficiency).
54
Section 10 - Troubleshooting
Fig. 74
N. GAS IGNITOR NOT WORKING
1. Gas pressure too low - The pressure inside a propane
tank decreases as the temperature drops, even to
the point of having zero pressure. Larger and/or
fuller tanks can withstand longer periods of colder
temperatures before losing all pressure. Therefore,
smaller, less full tanks will be more susceptible to
cold temperatures. In cold weather, tanks should be
kept full and the tank and hose should be sheltered.
2. Burn chamber obstructed - Clean the burn
chamber, especially at the end of the auger. Make
sure there is no ash or material inside the burn
chamber and that all of the combustion air holes are
open and unobstructed.
3. Aerator combustion air holes obstructed Remove aerator and clear deposits from combustion
air holes.
4. Ignitor wire loose - Make sure the connector on the
end of the ignitor is threaded on tightly and that the
ignitor wire has a good connection.
5. Electrode dirty or damaged - Clean the electrode
using a coarse cloth rag. If there is excessive
creosote or deposits on the electrode that are difficult
to remove, oven cleaner may be used to soften the
deposits. Inspect for cracked insulation, damage or
for any loose components.
6. Combustion fan obstructed - Inspect
combustion fan and remove any obstructions.
8. Burn chamber temperature is 300˚F or higher If the FireStar controller detects the temperature of
the burn chamber is at or above 300˚F (149˚C), the
gas ignitor will not light. Allow the burn chamber
to cool. To display the temperature of the burn
chamber, press the Water Temp
button. The
LED display will indicate the actual temperature of
the burner up to 999˚F or, if it is higher, as a decimal
representation (e.g., 1500˚F will display as 1.5).
NOTE: If the thermocouple in the burn chamber
becomes damaged or is faulty, the FireStar will
indicate a temperature of 300˚F (149˚C). If the
burn chamber is relatively cool and the FireStar
indicates 300˚F (149˚C), the thermocouple will
need to be replaced. Contact your Central Boiler
dealer.
the
7. Air proving switch tubes obstructed or
disconnected - Make sure the fan is operating. The
air tube from the back port (P1) of the air proving
switch connects to the nipple on the bottom of the
fan; the air tube from the front port (P2) of the air
proving switch is installed in the bracket on the
fan. Make sure both tubes are securely connected
to the correct port and are not kinked, cracked or
obstructed.
Section 10 - Troubleshooting
55
SECTION 11 – DECALS
NOTICE
Green
White
(Ground) (Neutral)
After appliance has been installed,
seal these holes with silicone to
prevent rodents from entering.
p/n 4122
Black
(Fire Star™
Controller Power)
Green
(Ground to
Electrical Box)
White
5 Amp
Green
115 VAC
Receptacle
Green
Black
(Line Voltage)
White
NOTICE
Fuse for
Fire Star
Controller
Maximum
Load 10 Amp
(From 15 Amp Breaker)
White
(Neutral)
Green
(Ground)
© 2006 Central Boiler
Ground Rod Kit
(p/n 6593) Recommended
p/n 5071
DO NOT operate this appliance
with this panel removed.
NOTICE
p/n 4125
DO NOT alter this
equipment in any way.
p/n 5073
!
CAUTION
!
HOT GASES - Keep face away when
viewing fire and from door area.
p/n 4120
CAUTION
HOT Surfaces
DO NOT Touch
During Operation
p/n 5079
56
Section 11 - Decals
SECTION 12 – WIRING DIAGRAMS
Maxim M255P
Wiring Diagram
ref.
PinColor Description
Voltage
1
Orange
Burner auger
120V
2
Yellow
Gas burner transformer 120V
3VioletFan
120V
4
Grey
Auxiliary auger (hopper)120V
5
Blue
Transfer auger
(and hopper)
120V
10White Neutral
120V
16
Black
Power to the board
120V
21
Black
Safety power/snap disc 120V
Section 12 - Wiring Diagram
PinColor
7
Violet
8 Green/Black
9
Red
18
Pink
19 Blue/Black
20Pink/Black
23 Grey/Black
24 Violet/Black
Description
Voltage
Fan control
5 VDC
Low voltage ground 5 VDC
Spare 5 VDC
5 VDC
Burn-back snap disc 5 VDC
Water level sensor
5 VDC
Relay/Ignition
confirmation
5 VDC
Spare I/O
5 VDC
Spare I/O
5 VDC
PinColor
12 Yellow/Black
13 Red/Black
14 Yellow
15 Yellow/White
Description
Voltage
Spare thermocouple
N/A
Thermocouple ground N/A
Water level
N/A
Burn chamber
N/A
57
SECTION 12 – WIRING DIAGRAMS
Control
Panel
Assembly
Main
Harness
Screw-on
Connector
Maxim M255 PE Models
Wiring Diagram
Electric Ignition
Water Level
Sensor
BLU/
Water
BLK
Temperature
Sensor
RED
Main Harness
Connector Pin Order
GRN/
BLK
1
5
BLK
Low Voltage
BLU
16GA
-
206837-1
High Voltage
Low Voltage
Transfer
Auger
WHT
Fuel Door
Transformer
RED
WHT
WHT
PNK
BLU
GRY
YEL
Ignition
Relay 2
(optional)
Ignition
Relay 1
R
C
Spare
Wires
GRN/
BLK
BLK
GRN
BLK
Burner
Limit
Snap Disc
BLK
GRY/BLK
VIO/BLK
YEL/WHT
RED
RED/BLK
Black
On Off
5 Amp
Breaker
To Ignition
Relay(s)
115VAC
Receptacle
Max Load
Ground
5 Amp
WHT
BLK
4
9
VIO GRN/ RED
BLK
18GA 18GA 18GA
RED/
YEL/
10 WHT - YEL RED BLK YEL WHT 15
TC TC 18GA 18GA 18GA
16GA
16 BLK
PNK BLU/ PNK/ 20
BLK
BLK
16GA
18GA 18GA 18GA
BLK
GRY/ VIO/ 24
21
16GA
BLK
BLK
18GA 18GA
SAFETY
High Limit
Snap Disc
YEL/
BLK
YEL
ORG YEL
VIO GRY
16GA 16GA 16GA 16GA
BLK
GRN
YEL
4
3
4
2
1
2
1
GRY
YEL
BLK
WHT
BLU
RED
1
Connect to 115VAC
Power Supply
15 Amp Min.
3
Air
Proving
Switch
VIO
RED/
BLK
WHT
Connected
to Hopper
Panel
Fuel
Door
Actuator
WHT
Igniter 1
Igniter 2
Burn Chamber
Thermocouple
WHT
Fan
WHT GRN
ORG
Burner Auger
GRN WHT
VIO
BLK
© 2014 Central Boiler, 6/14
PinColor Description
Voltage
1
Orange
Burner auger
120V
2
Yellow
Gas burner transformer 120V
3VioletFan
120V
4
Grey
Auxiliary auger (hopper)120V
5
Blue
Transfer auger
(and hopper)
120V
10White Neutral
120V
16
Black
Power to the board
120V
21
Black
Safety power/snap disc 120V
58
PinColor
7
Violet
8 Green/Black
9
Red
18
Pink
19 Blue/Black
20Pink/Black
23 Grey/Black
24 Violet/Black
Description
Voltage
Fan control
5 VDC
Low voltage ground 5 VDC
Spare 5 VDC
5 VDC
Burn-back snap disc 5 VDC
Water level sensor
5 VDC
Relay/Ignition
confirmation
5 VDC
Spare I/O
5 VDC
Spare I/O
5 VDC
PinColor
12 Yellow/Black
13 Red/Black
14 Yellow
15 Yellow/White
Description
Voltage
Spare thermocouple
N/A
Thermocouple ground N/A
Water level
N/A
Burn chamber
N/A
Section 12 - Wiring Diagram
SECTION 13 – PARTS LISTING
6797 (2)
4302
4099
11430
9533
Main Wiring
Harness
9068-132 (G)
9068-151 (T)
4089
4265
4264
100%
60%
60%
100%
61%
61%
5638-021 (T)
5638-202 (G)
6783-021 (T)
6783-202 (G)
9220
6784
10502-011
Controller
9257
809 (5)
9096-021
9096-202
809 (5)
4050022
Whole Door
9086 (T)
9886 (G)
9046-011
Gasket
Kit 2500054
Burn Chamber
9710
9622
2000181
4716
9268
3100582-101
10719
Motor
6000010
1085
3667
1200053-101
5349
9062
6000012
9504
4571
3100606-101
5348
9702
3044
4567
9527
3100607-101
9334
9012
3533
3100436-101
6180
Transition
3100597
9296
5349
1336
9297
*Kit includes all gaskets, bushings and plates
Section 13 - Parts Listing
3100583
6260
9124-021 (T)
9124-202 (G)
9125-021(T)
9125-202 (G)
3100588-101
3100591-101
3100584
3100585
10719
6257
2000182
3100587-101
Gasket
9224
3100586
9342
8200155
9243
9097
9221
Fan
9060
9058
9395
9146
9332
9105
9787
Color Code Reference
(T) = Terra Brown/Taupe
(G) = Green/Olive Gray
© 2013 Central Boiler
59
1-YEAR LIMITED WARRANTY
Central Boiler, Inc. ("Central Boiler") warrants to the original owner, except (a) parts manufactured by others and excluded from
warranty coverage below; and (b) parts or items specified below, Central Boiler Maxim furnaces against defects in workmanship for
a period of ONE (1) YEAR from the date of original retail purchase.
An optional 5-Year Warranty is available if a Limited Warranty Registration
Form is completed and sent to Central Boiler within ten (10) days of the original
owner taking possession of the furnace AND provided that one thermostatic
valve per set of supply and return lines is installed in the system.
If a defect exists, at its option Central Boiler will (1) repair the defective part at no charge, using new or refurbished replacement
parts, (2) exchange the furnace with a comparable model furnace that is new or which has been manufactured from new or serviceable
used parts and is at least functionally equivalent to the original furnace, or (3) refund the purchase price of the furnace based on the
pro-ration scale. A replacement furnace/part assumes the remaining warranty of the original furnace/part or ninety (90) days from the
date of replacement or repair, whichever provides longer coverage for you. If a furnace or part is qualified for replacement under the
provisions of this limited warranty, at Central Boiler's discretion, the furnace or part may be required to be returned to Central Boiler
for inspection and recycling or disposal.
Parts Manufactured By Others. Parts that are factory-installed by Central Boiler, but are manufactured by others, may be covered by
their own manufacturer's warranty and are not covered by this limited warranty, except the FireStar™ controller is warranted against
defects in workmanship for a period of two (2) years from the date of original retail purchase, provided that the Limited Warranty
Registration Form is completed and sent to the Central Boiler within ten (10) days of the original owner taking possession of the
furnace; otherwise this limited warranty shall be good for a period of ONE (1) YEAR from the date of original retail purchase. This
limited warranty covers the controller part only; service calls, mileage, and labor to diagnose the problem and install a new part are
not covered.
Parts Covered by a Limited One Year Warranty. The following parts are covered by a limited warranty for workmanship defects for
one year: aerator, burn chamber, thermocouple, hopper lid shock, chimney transition, firebox door parts, chimney box parts, paint,
burner assembly, auger, auger motor and fan.
This Limited Warranty applies only to Central Boiler Maxim outdoor furnaces. This limited warranty covers only those defects that
arise as a result of normal use of the outdoor furnace and does not cover any other defects or problems, including those that arise as
a result of: (a) improper maintenance (b) operation outside the furnace’s specifications, accident, abuse, misuse, misapplication, or
parts that are not factory-installed; (c) service performed by anyone other than Central Boiler unless authorized by Central Boiler in
writing; (d) modifications undertaken without the written permission of Central Boiler; or (e) if any Central Boiler serial number has
been removed or defaced. This warranty excludes the cost of shipping, labor to remove or reinstall the furnace, plumbing labor and/
or parts and the cost of alternative heat if the furnace is out of service for repairs. Warranty excludes replacement of water, inhibitors
or other additives, and parts used in the system whether or not mounted on the furnace, such as pumps, valves, and piping.
Central Boiler is not liable for damage or repairs required as a consequence of faulty installations or applications by others or any
event of force majeure. Central Boiler is not liable for incidents or accidents which can be prevented by the owner or that occur from
the operation of the outdoor furnace. A backup heating system must be in place to prevent damage in case of failure to refuel the
outdoor furnace or mechanical failure of the outdoor furnace or system occurs. Heat replacement representations found in Central
Boiler promotional information should be used only as a guideline. Heat loss for all applications with all weather extremes and other
heat variables must be considered when sizing an outdoor furnace for different applications.
THIS WARRANTY AND REMEDIES SET FORTH ABOVE ARE EXCLUSIVE AND IN LIEU OF ALL OTHER WARRANTIES,
REMEDIES AND CONDITIONS, WHETHER ORAL OR WRITTEN, EXPRESS OR IMPLIED. CENTRAL BOILER
SPECIFICALLY DISCLAIMS ANY AND ALL IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IF CENTRAL BOILER CANNOT LAWFULLY
DISCLAIM IMPLIED WARRANTIES UNDER THIS LIMITED WARRANTY, ALL SUCH WARRANTIES, INCLUDING
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE LIMITED IN DURATION
TO THE DURATION OF THIS WARRANTY. No Central Boiler dealer or employee is authorized to make any modification,
extension, or addition to this warranty. CENTRAL BOILER IS NOT RESPONSIBLE FOR DIRECT, SPECIAL, INCIDENTAL OR
CONSEQUENTIAL DAMAGES RESULTING FROM ANY BREACH OF WARRANTY OR CONDITION, OR UNDER ANY
OTHER LEGAL THEORY. Some states and provinces do not allow the exclusion or limitation of incidental or consequential damages
or exclusions or limitations on the duration of implied warranties or conditions, so the above limitations or exclusions may not apply
to you. This warranty gives you specific legal rights, and you may also have other rights that vary by state or province.
To obtain warranty service, contact the Central Boiler dealer from whom you purchased your furnace or contact Central Boiler by
telephone (800-248-4681) or mail (20502 160th Street, Greenbush, MN 56726). Please provide the dealer’s name, original date of
sale, model number and serial number in all communications. Central Boiler reserves the right to require the warranty service to be
performed at Central Boiler facility when deemed necessary by Central Boiler.
Printed in U.S.A.
©2015 Central Boiler
(p/n 9000311 - REV. A) - 15-MAY-2015
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