RheosTM

Installation and Operation Instructions Document 1170F

Installation and Operation

Instructions for

Rheos

TM

Modulating Boiler

Model RHCH

Modulating Water Heater

Model RHCV

U.S. Patent No. 6,644,393

Canada Patent Pending

FOR YOUR SAFETY: This product must be installed and serviced by a professional service technician, qualified in hot water boiler installation and maintenance. Improper installation and/or operation could create carbon monoxide gas in flue gases which could cause serious injury, property damage, or death.

Improper installation and/or operation will void the warranty.

WARNING

If the information in this manual is not followed exactly, a fire or explosion may result causing property damage, personal injury or loss of life.

Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance.

WHAT TO DO IF YOU SMELL GAS

• Do not try to light any appliance.

• Do not touch any electrical switch; do not use any phone in your building.

• Immediately call your gas supplier from a nearby phone. Follow the gas supplier's instructions.

• If you cannot reach your gas supplier, call the fire department.

Installation and service must be performed by a qualified installer, service agency, or gas supplier.

AVERTISSEMENT

Assurez-vous de bien suivres les instructions données dans cette notice pour réduire au minimum le risque d’incendie ou d’explosion ou pour éviter tout dommage matériel, toute blessure ou la mort.

Ne pas entreposer ni utiliser d’essence ni d’autres vapeurs ou liquides inflammables dans le voisinage de cet appareil ou de tout autre appareil.

QUE FAIRE SI VOUS SENTEZ UNE ODEUR DE GAZ:

• Ne pas tenter d’allumer d’appareils.

• Ne touchez à aucun interrupteur. Ne pas vous servir des téléphones dansle bâtiment où vous vous trouvez.

• Appelez immédiatement votre fournisseur de gaz depuis un voisin. Suivez les instructions du fournisseur.

• Si vous ne pouvez rejoindre le fournisseur de gaz, appelez le sservice des incendies.

L’installation et l’entretien doivent être assurés par un installateur ou un service d’entretien qualifié ou par le fournisseur de gaz.

Page 2

LAARS Heating Systems

TABLE OF CONTENTS

SECTION 1.

General Information

1.1 Introduction ........................................................ 3

1.2 Model Identification ............................................ 3

1.3 Warranty ............................................................ 4

1.4 Dimensions ........................................................ 4

1.5 Outdoor Installations .......................................... 6

1.6 Locating the Appliance ....................................... 6

1.7 Locating Pump-Mounted Water

Heater with Respect to Storage Tank(s) ............ 6

1.8 Locating Pump-Mounted Boiler with

Respect to Return/Supply Header ..................... 6

1.9 Locating Appliance for Correct Vent Distance

From Outside Wall or Roof Termination ............. 6

5.5.1 Temperature Setpoint ...................................... 24

5.5.2 Differential Setting ............................................ 24

5.5.3 Offset ............................................................... 24

5.5.4 Throttling Range .............................................. 24

5.5.5 Minimum Output Setting .................................. 24

5.5.6 Integration Constant ........................................ 24

5.6 External Control Connections .......................... 25

5.7 Wiring Diagrams .............................................. 25

SECTION 6.

Operating Instructions

6.1 Filling the Boiler System .................................. 38

6.2 Operating the Burner and Set Up .................... 38

6.3 Shutting Down the Rheos ................................ 40

6.4 To Restart the Rheos ....................................... 40

SECTION 2.

Venting and Combustion Air

2.1 Combustion Air .................................................. 7

2.1.1 Combustion Air From Room .............................. 7

2.1.2 Intake Combustion Air ........................................ 7

2.2 Venting ............................................................... 9

2.3 Locating Vent & Combustion Air Terminals ........ 9

2.3.1 Side Wall Vent Terminal ..................................... 9

2.3.2 Side Wall Combustion Air Terminal ...................11

2.3.3 Vertical Vent Terminal .......................................11

2.3.4 Vertical Combustion Air Terminal ..................... 15

2.4 Common Vent Test – Boilers ............................ 15

SECTION 3.

Gas Supply and Piping

3.1 Gas Supply and Piping .................................... 15

SECTION 4A.

Water Connections – Rheos Boiler

4A.1 Heating System Piping:

Hot Supply Connections – Boiler ..................... 18

4A.2 Cold Water Make-Up – Boiler .......................... 18

4A.3 Water Flow Requirements – Boiler .................. 18

4A.4 Freeze Protection – Boiler ............................... 19

SECTION 7.

Maintenance

7.1 System Maintenance ....................................... 40

7.2 Appliance Maintenance and

Component Description ................................... 40

7.2.1 Burner .............................................................. 41

7.2.2 Filter ................................................................. 41

7.2.3 Modulating Gas Valve ...................................... 41

7.2.4 Safety Gas Valve ............................................. 41

7.2.5 Manual Reset High Limit Control ..................... 41

7.2.6 Temperature Control ........................................ 41

7.2.7 Ignition Control ................................................. 41

7.2.8 Ignitor / Flame Sensor Assembly ..................... 42

7.2.9 Transformers .................................................... 42

7.2.10 Blower............................................................ 42

7.2.11 Flow Switch .................................................... 42

7.2.12 Heat Exchanger Coil...................................... 42

7.2.13 Normally Open Vent Valve ............................. 43

7.2.14 Motorized Safety Valve .................................. 43

7.2.15 Gas Pressure Switches ................................. 44

SECTION 4B.

Water Connections – Rheos Water Heater

4B.1 Water System Piping – Water Heater .............. 19

4B.2 Hot Water Supply Piping – Water Heater ......... 19

4B.3 Water Flow Requirements – Water Heater ...... 20

4B.4 Combined Water (potable)

Heating and Space Heating ............................. 20

4B.5 Freeze Protection — Water Heater .................. 20

SECTION 8.

Trouble Shooting

8.1 Sequence of Operation .................................... 45

8.2 Resolving Lockouts .......................................... 45

8.3 Delayed Ignition – Possible Causes ................ 45

8.3.1 High Lockup Pressure (LP Appliances)

- Occurs on Start-up ........................................ 45

8.3.2 Gas Valve Regulation ...................................... 45

8.3.3 Defective Burner - Occurs on

Startup or at Burner Shutdown ........................ 46

8.4 Short Cycling – Boiler ...................................... 46

8.5 Short Cycling – Water Heater .......................... 46

8.6 High Gas Consumption .................................... 46

SECTION 5.

Electrical Connections

5.1 Main Power ...................................................... 21

5.2 Pump Connections .......................................... 21

5.3 Temperature Control – Boiler ........................... 21

5.4 Temperature Control – Water Heater ............... 21

5.4.1 Remote Water Heater Temperature Control .... 21

5.4.2 Internal Water Heater Temperature Control ..... 22

5.5 Temperature Control Features ......................... 22

SECTION 9.

Replacement Parts

9.1 General Information ......................................... 46

9.2 Parts List .......................................................... 47

Tables Listing

................................................................. 56

Figures Listing

.............................................................. 56

Rheos Boiler and Water Heater

SECTION 1.

General Information

USING THIS MANUAL – Because the Rheos

Boilers and Rheos Water Heaters are identical appliances, with the exception of materials of manufacture, labels and ultimate use application, this manual provides information for the proper installation, operation and maintenance of both products. Where differences exist between the application of the appliances and their operation, the sections pertinent to only one appliance or the other will be so identified.

WARNING

The Rheos hydronic, boiler or water heater must be installed in accordance with the procedures detailed in this manual, or the Laars Heating Systems warranty will be voided. The installation must conform to the requirements of the local jurisdiction having authority, and, in the United States, to the latest edition of the National Fuel Gas Code, ANSI

Z223.1/NFPA54. In Canada, the installation must conform to the latest edition of CSA B149.1 Natural

Gas and Propane Gas Installation Code, and/or local codes. Where required by the authority having jurisdiction, the installation of Rheos boilers must conform to the Standard for Controls and Safety

Devices for Automatically Fired Boilers, ANSI/ASME

CSD-1. Any modifications to the boiler, its gas controls, or wiring may void the warranty. If field conditions require modifications, consult the factory representative before initiating such modifications.

1.1 Introduction

This manual provides information necessary for the installation, operation, and maintenance of Laars

Heating Systems Rheos (copper tube or cupronickel tubes) appliances. Read it carefully before installation.

All application and installation procedures should be reviewed completely before proceeding

Page 3 with the installation. Consult the Laars Heating

Systems factory, or local factory representative, with any problems or questions regarding this equipment.

Experience has shown that most operating problems are caused by improper installation.

The Rheos appliance is protected against over pressurization. A pressure relief valve is fitted to all appliances. It is installed inside the jacket, at the water outlet of the unit.

IMPORTANT: The inlet gas pressure to the appliance must not exceed 13" W.C. (3.2kPa).

All installations must be made in accordance with 1) American National Standard Z223.1/NFPA54-

Latest Edition “National Fuel Gas Code” or 2) CSA

B149.1 “Natural Gas and Propane Installation Code” and with the requirement of the local utility or other authorities having jurisdiction. Such applicable requirements take precedence over the general instructions contained herein.

All electrical wiring is to be done in accordance with the local codes, or in the absence of local codes, with: 1) The National Electrical Code ANSI/NFPA No.

70-latest Edition, or 2) CSA STD. C22.1 “Canadian

Electrical Code - Part 1”. This appliance must be electrically grounded in accordance with these codes.

1.2 Model Identification

Consult the rating plate on the unit. The following information describes the model number structure.

(1-2) Model Series Designation

R H = Rheos mid-sized commercial

(3) Model Efficiency

C = Mid Efficiency (non-condensing)

H = High Efficiency (condensing)

(4) Usage

H = Hydronic

V = Volume Water

(5-8) Size

1 2 0 0 = 1,200,000 BTU/hr input

1 6 0 0 = 1,600,000 BTU/hr input

2 0 0 0 = 2,000,000 BTU/hr input

2 4 0 0 = 2,400,000 BTU/hr input

1 2 3

R H

4 5 6 7 8

0 0

SERIES

R H C

H

USAGE

H

V

1

1

2

2

0

4

2

6

SIZE

0

0

0

0

0

0

0

0

Model Designation

9 10 11

A

12

F

FUEL

N

P

ALTITUDE

A

LOCATION

I

C

F

13 14 15 16

REVISION

1

2

HEAT

EXCHANGER

E

F

F

G

D

E

B

C

OPTION

CODES

X

A

N

S

X

H

Page 4

(9) Fuel

N = Natural Gas

P = Liquid Propane

(10) Altitude

A = Universal Altitude (0' to 10,000') (0m to 3050m)

(11) Location

C = Indoor and Outdoor (for non-condensing units)

I = Indoor (for condensing units)

(12) Firing Mode

F = Modulating

(13) Revision

1 = First version

2 = Second version

(14) Heat Exchanger

E = Glass-lined steel with copper tubes

F = Glass-lined steel with cupronickel tubes

(15) Control Option Code

X = Standard, meets CSD-1 boiler standard

A = Control Pack A: CSD-1, CA, FM, IL, IRI,

Alarm Bell

B = Control Pack B: CSD-1, CA, FM, IL, LDS, MN

C = Control Pack C: with 200°F (93°C) max.

control (KY)

D = Control Pack A with 200°F (93°C) max. control

E = Control Pack B with 200°F (93°C) max. control

F = Non CSD-1

G = Non CSD-1 with 200°F (93°C) max. control

(16) Pump Options

X = No Pump

H = Pump mounted, hard water pump

N = Pump mounted, normal pump

S = Pump mounted, soft water pump (volume water, high efficiency (condensing) model only)

LAARS Heating Systems

1.3 Warranty

Laars Heating Systems’ Rheos appliances are covered by a limited warranty. The owner should fill out the warranty registration card and return it to Laars

Heating Systems.

All warranty claims must be made to an authorized Laars Heating Systems representative or directly to the factory. Claims must include the serial number and model (this information can be found on the rating plate), installation date, and name of the installer. Shipping costs are not included in the warranty coverage.

Some accessory items are shipped in separate packages. Verify receipt of all packages listed on the packing slip. Inspect everything for damage immediately upon delivery, and advise the carrier of any shortages or damage. Any such claims should be filed with the carrier. The carrier, not the shipper, is responsible for shortages and damage to the shipment whether visible or concealed.

1.4 Dimensions

The overall dimensions are 34.5" (88cm) wide, 65.75" (167cm) tall, 55" (140cm) deep. Other dimensions can be found in Figure 1.

Rheos Boiler and Water Heater

"G" GAS CONNECTION

"V" FLUE VENT (CAT. IV) OUTLET

"A" AIR INLET

WITH AIR FILTER

"P" WATER INLET PUMP-MOUNTED UNIT

"S" WATER OUTLET

"W" WATER INLET

NON-PUMP-MOUNTED UNIT

53

135

65.75

167

48

122

30.5

77

D

C

B

13

33

17.25

44

55

140

7.75

20

3.75

10

34.5

88

Model "V" Vent Outlet

Connection

1200

1600

2000

2400 inches

6

6

7

10

cm

15

15

18

25

"A" Air Inlet Connection inches

6

8

8

8

cm

15

20

20

20

"W" Inlet Water

Connection Non-

Pump-Mounted

NPT

2-1/2"

2-1/2"

3"

3"

Dimensions shown in inches cm.

"P" Inlet Water

Connection Pump-

Mounted

NPT

2-1/2"

3"

2-1/2"

3"

"S" Outlet Water

Connection All

Models

NPT

2-1/2"

2-1/2"

3"

3"

Model

1200

1600

2000

2400

"G" Gas Connects. Std/Control

Pk A Nat/LP

NPT

1"

1-1/2"

1-1/2"

1-1/2"

Figure 1. Dimensional Drawing.

Control

Pk B & E

Nat

NPT

1-1/2"

2"

2"

2"

Control

Pk B & E

LP

NPT

1-1/2"

2"

1"

2" inches

34-1/4

34-1/4

34-1/4

32

"B"

cm

inches

87

27-3/4

87

87

81

25-1/2

24-3/4

22-1/2

"C"

cm

inches

70

9-3/4

65

63

57

10-1/2

9-3/4

10-1/2

"D"

cm

25

27

25

27

Page 5

Page 6

1.5 Outdoor Installations

Attach the appropriate termination and appliance adaptor to the vent outlet (see Table 1). Units are shipped with a louvered cover over the ducted air connection. Do not remove this cover, and/or add any piping to the ducted air connection. The unit will take its combustion air through the louvers in the jacket.

WARNING

The outdoor terminal gets hot. Unit must be installed in such a way as to reduce the risk of burns from contact with the vent terminal.

Model (Size)

1200

1600

2000

2400

Termination

D2008300

D2008300

D2008400

D2007500

Appliance Adapter

D2008500

D2008500

D2008600

D2007600

Table 1. Terminals for Outdoor Installation.

In installations where the air temperature may go below 15°F (-9°C), a valve heater kit, part number

R2010100, must be installed on the operating gas valve. Instructions for the installation of the valve heater are included with the kit.

NOTE: Units built with control packs B and E have two actuators. Therefore, two heater kits must be used.

1.6 Locating the Appliance

The appliance should be located to provide clearances on all sides for maintenance and inspection.

It should not be located in an area where leakage of any connections will result in damage to the area adjacent to the appliance or to lower floors of the structure.

When such a location is not available, it is recommended that a suitable drain pan, adequately drained, be installed under the appliance.

The appliance is design certified by CSA-

International for installation on combustible flooring; in basements; in closets, utility rooms or alcoves.

Rheos Boilers or Water Heaters must never be

installed on carpeting. The location for the appliance should be chosen with regard to the vent pipe lengths and external plumbing. The unit shall be installed such that the gas ignition system components are protected from water (dripping, spraying, rain, etc.) during operation and service (circulator replacement, control replacement, etc.). When vented vertically, the Rheos must be located as close as practical to a chimney or gas vent. If the vent terminal and/or combustion air terminal terminate through a wall, and there is potential for snow accumulation in the local area, both terminals should be installed at an appropriate level above grade.

LAARS Heating Systems

The dimensions and requirements that are shown in Table 2 should be met when choosing the locations for the appliance:

Appliance

Surface

Piping Side

Opposite Side

Top

Back

Front

Vent

1

1

1

1

1

Required

Clearance From

Combustible Material inches cm

2.5

2.5

2.5

2.5

2.5

Suggested

Service

Clearance inches

cm

24

24

24

36

36 per UL1738 venting system supplier's instructions

61

61

61

91

91

Table 2. Clearances.

1.7 Locating Pump-Mounted Water Heater with Respect to Storage Tank(s)

For best results a pump-mounted Rheos water heater should be located within 15 feet (4.6m) of the storage tank(s). The pump is sized for 30 feet (9.1m) of piping.

Water heater pumps are sized for water hardness;

7.6 to 17 grains per gallon for normal water, and greater than 17 grains per gallon for hard water. If the system has soft water (1 to 7.5 grains per gallon hardness), but the Rheos has a normal water pump mounted in it, please consult the factory for assistance.

If the appliance must be installed with longer piping runs, then larger diameter pipe or tubing may be able to be used, in some instances. Consult the factory for assistance.

1.8 Locating Pump-Mounted Boiler with

Respect to Return/Supply Header

For the best results a pump-mounted Rheos

Boiler should be located within 15 feet (4.6m) of the supply and return headers. The pump is sized for

30 feet (9.1m) of piping, in most cases, enough for primary-secondary piping systems.

If the appliance must be installed with longer piping runs, then larger diameter tubing may be able to be used, in some instances. Consult the factory for assistance.

1.9 Locating Appliance for Correct Vent

Distance From Outside Wall or

Roof Termination

The forced draft combustion air blower in the appliance has sufficient power to vent properly when the guidelines in Table 3 are followed.

NOTE: When located on the same wall, the Rheos combustion air intake terminal must be installed a minimum of 12" (30cm) below the exhaust vent terminal and separated by a minimum of 36 inches

(91cm) horizontally.

Rheos Boiler and Water Heater

Page 7

Model

1200

1600

2000

2400

Intake

Size

6" (15 cm) dia.

8" (20 cm) dia.

8" (20 cm) dia.

8" (20 cm) dia.

Exhaust

Size

6" (15 cm) dia.

6" (15 cm) dia.

7" (18 cm) dia.

10" (25 cm) dia.

Intake

Maximum Run

50 linear feet with 5 elbows

50 linear feet with 5 elbows

50 linear feet with 5 elbows

50 linear feet with 5 elbows

Exhaust

Maximum Run

50 linear feet with 5 elbows

50 linear feet with 5 elbows

50 linear feet with 5 elbows

50 linear feet with 5 elbows

SECTION 2.

Venting and Combustion Air

2.1 Combustion Air

Table 3. Vent / Air Pipe Sizes.

Rheos boilers and water heaters must have provisions for combustion and ventilation air in accordance with section 5.3, Air for Combustion and

Ventilation, of the National Fuel Gas Code, ANSI

Z223.1, or Sections 7.2, 7.3 or 7.4 of CSA B149.1,

Installation Codes, and applicable provisions of the local building codes.

A Rheos unit can take combustion air from the space in which it is installed, or the combustion air can be ducted directly to the unit. Ventilation air must be provided in either case.

2.1.1 Combustion Air From Room

In the United States, the most common requirements specify that the space shall communicate with the outdoors in accordance with method 1 or 2, which follow. Where ducts are used, they shall be of the same cross-sectional area as the free area of the openings to which they connect.

Method 1: Two permanent openings, one commencing within 12" (300mm) of the top and one commencing within 12" (300mm) of the bottom, of the enclosure shall be provided. The openings shall communicate directly, or by ducts, with the outdoors or spaces that freely communicate with the outdoors.

When directly communicating with the outdoors, or when communicating to the outdoors through vertical ducts, each opening shall have a minimum free area of 1 square inch per 4000 Btu/hr (550 square mm/kW) of total input rating of all equipment in the enclosure.

When communicating to the outdoors through horizontal ducts, each opening shall have a minimum free area of not less than 1 square inch per 2000 Btu/hr

(1100 square mm/kW) of total input rating of all equipment in the enclosure.

Method 2: One permanent opening, commencing within 12" (300mm) of the top of the enclosure, shall be permitted. The opening shall directly communicate with the outdoors or shall communicate through a vertical or horizontal duct to the outdoors or spaces that directly communicate with the outdoors and shall have a minimum free area of 1 square inch per 3000

Btu/hr (734 square mm/kW) of the total input rating of all equipment located in the enclosure. This opening must not be less than the sum of the areas of all vent connectors in the confined space.

Other methods of introducing combustion and ventilation air are acceptable, providing they conform to the requirements in the applicable codes listed above.

In Canada, consult local building and safety codes or, in absence of such requirements, follow

CAN/CGA B149.

2.1.2 Intake Combustion Air

The combustion air can be taken through the wall, or through the roof. When taken from the wall, it must be taken from out-of-doors by means of the Laars horizontal wall terminal, shown in Table 4. See Table 3 to select the appropriate diameter air pipe. When taken from the roof, a field-supplied rain cap or an elbow arrangement must be used to prevent entry of rain water (see Figure 2).

Use single-wall galvanized pipe for the combustion air intake (see Table 5), sized per Section

1.8. Route the intake to the heater as directly as possible. Seal all joints with tape. Provide adequate hangers. The unit must not support the weight of the combustion air intake pipe. Maximum linear pipe length allowed is 50 feet (15.2m). Up to five elbows can be used with the 50 feet of pipe. Subtract 10 allowable linear feet for every additional elbow used.

Figure 2. Combustion Air and Vent Through Roof.

Page 8

LAARS Heating Systems

U.S. Installations (see note 1)

A= Clearance above grade, veranda, porch, 12 inches (30 cm) deck, or balcony

Canadian Installations (see note 2)

12 inches (30 cm)

B= Clearance to window or door that may be 4 feet (1.2 m) below or to side of opening; 36 inches (91 cm) opened 1 foot (30 cm) above opening

See note 5 C= Clearance to permanently closed window See note 4

D= Vertical clearance to ventilated soffit located above the terminal within a horizontal distance of 2 feet (61cm) from the center line of the terminal

See note 4 See note 5

E= Clearance to unventilated soffit

F= Clearance to outside corner

See note 4

See note 4

G= Clearance to inside corner See note 4

H= Clearance to each side of center line extended above meter/regulator assembly See note 4

See note 5

See note 5

See note 5

3 feet (91 cm) within a height 15 feet above the meter/regulator assembly

I= Clearance to service regulator vent outlet See note 4

J= Clearance to nonmechanical air supply inlet to building or the combustion air inlet to any other appliance

3 feet (91 cm)

4 feet (1.2 m) below or to side of opening; 36 inches (91 cm)

1 foot (30 cm) above opening

K= Clearance to a mechanical air supply inlet 3 feet (91 cm) above if within 10 feet (3 m) 6 feet (1.83 m) horizontally

L= Clearance above paved sidewalk or paved for category IV appliances. For Category III terminate directly above a sidewalk or paved driveway located on public property

Vent termination not allowed in this location for

Vent termination not allowed in this location category IV appliances. A vent shall not appliances, vent must terminate at least 7 driveway that is located between two single feet (2.13m) above the sidewalk or driveway. family dwellings and serves both dwellings.

For Category III appliances that do not violate the previous condition, vent must terminate at least 7 feet (2.13m) above the sidewalk or driveway.

M= Clearance under veranda, porch, deck, or balcony

See note 4 12 inches (30 cm) (see note 3)

Notes:

1. In accordance with the current ANSI Z223.1 / NFPA 54 National Fuel Gas Code.

2. In accordance with the current CAN/CGA-B149 Installation Codes.

3. Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.

4. For clearances not specified in ANSI Z223.1 / NFPA 54, clearance is in accordance with local installation codes and the requirements of the

gas supplier.

5. For clearances not specified in CAN/CGA-B149, clearance is in accordance with local installation codes and the requirements of the gas

supplier.

Figure 3. Combustion Air and Vent Through Side Wall.

Rheos Boiler and Water Heater

Page 9

Model

1200

1600

2000

2400

Horizontal Combustion

Air Terminal

20260701

20260703

20260703

20260703

Horizontal Vent

Terminal

D2004500

D2004500

D2004600

D2006200

Table 4. Horizontal Vent and Air Terminals

For Indoor Installations.

Term

Pipe

Description

Single-wall galvanized steel pipe, 24 gauge minimum (sized per section 1.9)

Permanent duct tape or aluminum tape Joint

Sealing

Insulation Not required, but recommended R5 insulation for cold installations (consult American Society of Heating, Refrigerating, and Air Conditioning

Engineers (ASHRAE) handbook)

Table 5. Required Combustion Air Piping Material.

The connection for the intake air pipe is in the back of the unit. Take the plate off the back to reveal the collar on the filter box. Run a bead of silicone around the collar and slide the pipe over the collar.

Secure with sheet metal screws.

In addition to air needed for combustion, air shall also be supplied for ventilation, including all air required for comfort and proper working conditions for personnel. The Rheos loses less than 1 percent of its input rating to the room, but other heat sources may be present.

2.2 Venting

The Rheos is a Category IV appliance and must be installed with a stainless steel venting system that complies with the UL 1738 Standard (see Table

6). It must be installed per this installation manual and the venting system manufacturer’s Installation

Instructions. The unit’s vent can terminate through the roof, or through an outside wall. It can be installed through walls that are from 3" (7.6cm) to 12" (30cm) in thickness.

See Table 3 to select the appropriate vent pipe diameter. The first section of venting attached to the boiler must include a condensate drain fitting and condensate trap. Route the vent pipe to the heater as directly as possible. Seal all joints and provide adequate hangers as required in the venting system manufacturer’s Installation Instructions. Horizontal portions of the venting system must be supported to prevent sagging and may not have any low sections that could trap condensate. The unit must not support the weight of the vent pipe. Horizontal runs must slope upwards not less than ¼ inch per foot (21mm/m) from the unit to the vent terminal. Up to five elbows can be used with the 50 feet (15.2m) of pipe. Subtract 10 allowable linear feet for every additional elbow used.

IMPORTANT NOTE ABOUT COMMON VENTING:

A single vent that is shared by multiple Rheos units MUST be engineered by a competent venting specialist, and involves the selection of draft inducing equipment, hardware and controls to properly balance flue gas pressures. Do not common vent Rheos units unless the vent system meets this requirement.

Rheos units are never permitted to share a vent with

Category I applliances.

For outdoor applications, see Section 1.5.

Condensate Drain Connection: A condensate drain connection shall be provided on the first section of venting attached to the boiler. Connect a clear plastic tube between that drain connection on the vent and a floor drain (or optional condensate pump if a floor drain is not accessible). The plastic tube shall be formed into a loop (trap) to drain condensate that collects in the vent system without permitting flue gases to escape. The condensate drain must be installed so as to prevent accumulation of condensate.

Consult local codes for disposal method.

Term

Venting

System

Description

Heat-Fab®, Inc. Saf-T Vent®GC or CI,

Metal-Fab®, Inc. Corr/Guard, or equivalent sealed stainless steel system certified to UL1738.

Insulation Not required, but recommended R5 insulation with protective cover for cold installations (consult American Society of

Heating, Refrigerating, and Air Conditioning

Engineers (ASHRAE) handbook)

Table 6. Required Venting Material.

2.3 Locating Vent & Combustion Air

Terminals

2.3.1 Side Wall Vent Terminal

The appropriate Laars side wall vent hood must be used, and is listed in the installation and operation manual. The terminal provides a means of installing the vent piping through the building wall, and must be located in accordance with ANSI Z223.1/NFPA 54 and applicable local codes. In Canada, the installation must be in accordance with CSA B149.1 or .2 and local applicable codes. Consider the following when installing the terminal:

1. The figure in this addendum shows the requirements for mechanical vent terminal clearances for the U.S. and Canada.

2. Vent terminals for condensing appliances or appliances with condensing vents are not permitted to terminate above a public walkway, or over an area where condensate or vapor could create a nuisance or hazard.

Page 10

LAARS Heating Systems

3. Locate the vent terminal so that vent gases cannot be drawn into air conditioning system inlets.

4. Locate the vent terminal so that vent gases cannot enter the building through doors, windows, gravity inlets or other openings. Whenever possible, locations under windows or near doors should be avoided.

5. Locate the vent terminal so that it cannot be blocked by snow. The installer may determine that a vent terminal must be higher than the minimum shown in codes, depending upon local conditions.

6. Locate the terminal so the vent exhaust does not settle on building surfaces or other nearby objects. Vent products may damage such surfaces or objects.

7. If the boiler or water heater uses ducted combustion air from an intake terminal located on the same wall, locate the vent terminal at least

3 feet (0.9m) horizontally from the combustion air terminal, and locate the vent terminal at least

1 foot (0.3m) above the combustion air terminal.

From Massachusetts Rules and Regulations

248 CMR 5.08:

(a) For all side wall horizontally vented gas fueled equipment installed in every dwelling, building or structure used in whole or inpart for residential purposes, including those owned or operated by the Commonwealth and where the side wall exhaust vent termination is less than seven (7) feet above finished grade in the area of the venting, including but not limited to decks and porches, the following requirements shall be satisfied:

1. INSTALLATION OF CARBON MONOXIDE

DETECTORS.

At the time of installation of the side wall horizontal vented gas fueled equipment, the installing plumber or gasfitter shall observe that a hard-wired carbon monoxide detector with an alarm and battery back-up is installed on the floor level where the gas equipment is to be installed. In addition, the installing plumber or gasfitter shall observe that a battery operated or hard-wired carbon monoxide detector with an alarm is installed on each additional level of the dwelling, building or structure served by the side wall horizontal vented gas fueled equipment.

It shall be the responsibility of the property owner to secure the services of qualified licensed professionals for the installation of hard-wired carbon monoxide detectors.

a. In the event that the side wall horizontally vented gas fueled equipment is installed in a crawl space or an attic, thehardwired carbon monoxide detector with alarm and battery back-up may be installed on the next adjacent floor level.

b. In the event that the requirements of this subdivision cannot be met at the time of completion of installation, the owner shall have a period of thirty (30) days to comply with the above requirements; provided, however, that during said thirty (30) day period, a battery operated carbon monoxide detector with an alarm shall be installed.

2. APPROVED CARBON MONOXIDE

DETECTORS.

Each carbon monoxide detector as required in accordance with the above provisions shall comply with NFPA 720 and be ANSI/UL 2034 listed and IAS certified.

3. SIGNAGE.

A metal or plastic identification plate shall be permanently mounted to the exterior of the building at a minimum height of eight (8) feet

Model and

Gas Type

1200 natural

1200 propane

1600 natural

1600 propane

2000 natural

2000 propane

2400 natural

0-50 feet 0-15m

2"

1-1/2"

2-1/2"

2"

2-1/2"

2-1/2"

2-1/2"

5.1cm

3.8cm

6.4cm

5.1cm

6.4cm

6.4cm

6.4cm

Distance from Gas Meter or Last Stage Regulator

50-100 feet 15-31m

2-1/2"

2"

2-1/2"

2"

3"

2-1/2"

3"

6.4cm

5.1cm

6.4cm

5.1cm

7.6cm

6.4cm

7.6cm

100-200 feet 31-61m

2-1/2"

2"

3"

2-1/2"

3"

2-1/2"

3"

2400 propane 2" 5.1cm 2-1/2" 6.4cm 2-1/2"

Notes: 1. These figures are based on 1/2" 0.12kPa water column pressure drop.

2. Check supply pressure and local code requirements before proceeding with work.

3. Pipe fittings must be considered when determining gas pipe sizing.

6.4cm

5.1cm

7.6cm

6.4cm

7.6cm

6.4cm

7.6cm

6.4cm

Table 7. Gas Piping Sizes.

200-300 feet

3"

2-1/2"

3"

2-1/2"

3-1/2"

3"

3-1/2"

3"

61-91m

7.6cm

6.4cm

7.6cm

6.4cm

8.9cm

7.6cm

8.9cm

7.6cm

Rheos Boiler and Water Heater

Page 11 above grade directly in line with the exhaust vent terminal for the horizontally vented gas fueled heating appliance or equipment. The sign shall read, in print size no less than one-half (½) inch in size, “GAS VENT DIRECTLY BELOW.

KEEP CLEAR OF ALL OBSTRUCTIONS”.

4. INSPECTION.

The state or local gas inspector of the side wall horizontally vented gas fueled equipment shall not approve the installation unless, upon inspection, the inspector observes carbon monoxide detectors and signage installed in accordance with the provisions of 248 CMR

5.08(2)(a) 1 through 4.

(b) EXEMPTIONS: The following equipment is exempt from 248 CMR 5.08(2)(a) 1 through 4:

1. The equipment listed in Chapter 10 entitled

“Equipment Not Required To Be Vented” in the most current edition of NFPA 54 as adopted by the Board; and

2. Product Approved side wall horizontal vented gas fueled equipment installed in a room or structure separate from the dwelling, building or structure used in whole or in part for residential purposes.

(c) MANUFACTURER REQUIREMENTS

– GAS EQUIPMENT VENTING SYSTEM

PROVIDED. When the manufacturer of

Product Approved side wall horizontally vented gas equipment provides a venting system design or venting system components with the equipment, the instructions provided by the manufacturer for installation of the equipment and the venting system shall include:

1. Detailed instructions for the installation of the venting system design or the venting system components; and

2. A complete parts list for the venting system design or venting system.

(d) MANUFACTURER REQUIREMENTS –

GAS EQUIPMENT VENTING SYSTEMNOT

PROVIDED. When the manufacturer of a

Product Approved side wall horizontally vented gas fueled equipment does not provide the parts for venting the fuel gases, but identifies “special venting systems”, the following requirements shall be satisfied by the manufacturer:

1. The identification of each “special venting system” shall include either the listing of the website, phone number or manufacturer’s address where the venting system installation instructions can be obtained; and

2. The “special venting systems” shall be Product

Approved by the Board, and the instructions provided with that system shall include a parts list and detailed installation instructions.

(e) A copy of all installation instructions for the

Product Approved side wall horizontally vented gas fueled equipment, and all the venting instructions, parts lists, and/or design instructions for the venting system shall remain with the appliance or equipment at the completion of the installation.

Manufacturers' websites where venting system installation instructions may be obtained is located on the Laars website at: http://www.

laars.com.

2.3.2 Side Wall Combustion Air Terminal

The Laars side wall combustion air terminal (see

Table 4) must be used when the heater takes air from a side wall. Consider the following when installing the terminal:

1. Do not locate the air inlet terminal near a source of corrosive chemical fumes (e.g., cleaning fluid, chlorine compounds, etc.)

2. Locate the terminal so that it will not be subject to damage by accident or vandalism. It must be at least 7 feet (2.1m) above a public walkway.

3. Locate the combustion air terminal so that it cannot be blocked by snow. The National Fuel

Gas Code requires that it be at least 12 inches

(30cm) above grade, but the installer may determine it should be higher, depending upon local conditions.

4. If the Rheos is side-wall vented to the same wall, locate the vent terminal at least 3 feet (0.9m) horizontally from the combustion air terminal, and locate the vent terminal at least 1 foot (0.3m) above the combustion air terminal (see Figure 3).

2.3.3 Vertical Vent Terminal

When the unit is vented through the roof, the vent must extend at least 3 feet (0.9m) above the point at which it penetrates the roof. It must extend at least

2 feet (0.6m) higher than any portion of a building within a horizontal distance of 10 feet (3.0m), and high enough above the roof line to prevent blockage from snow. When the combustion air is taken from the roof, the combustion air must terminate at least 12" (30cm) below the vent terminal (see Figure 2).

Page 12

OPTIONAL PUMP MOUNTED UNIT AVAILABLE

LAARS Heating Systems

BOILER CIRC.

PUMP

COLD WATER

MAKE-UP

SYSTEM

RETURN

SYSTEM

SUPPLY

LEGEND

THERMOMETER

TEMPERATURE

SENSOR

GLOBE VALVE

PURGE

VALVE

CHECK VALVE

PRESSURE REDUCING VALVE

W/ FAST FILL BYPASS

D C

EXPANSION TANK

WITH AIR SCOOP AND

AUTO AIR VENT

3-WAY VALVE

VALVE

PUMP

D C

PRIMARY/SECONDARY MANDITORY FOR ALL

VARIABLE FLOW SYSTEMS

INSTALL AIR VENTS AT HIGH POINTS IN SYSTEM

PIPING & SIZING OF EXPANSION TANK

PER TANK MANUFACTURER'S INSTRUCTIONS

DIMENSION ''C'' TO BE 4 PIPE DIAMETERS

DIMENSION ''D'' TO BE 18" MINIMUM

CAUTION: THIS DRAWING SHOWS SUGGESTED

PIPING CONFIGURATION AND VALVING. CHECK

WITH LOCAL CODES AND ORDINANCES FOR

ADDITIONAL REQUIREMENTS.

SYSTEM PUMP

BOILER CIRCUIT PIPING MUST BE EQUAL TO

BOILER WATER CONNECTION SIZE

BOILER CIRC. PUMP SIZED FOR FLOW THROUGH BOILER

BOILER CIRC. PUMP TO BE USED WITH EM

2

SYSTEM TEMP. INTERLOCK REQUIRED

DOTTED DEVICES INDICATE ALTERNATE LOCATIONS

MULTIPLE STAGE BOILERS RECOMMENDED

Figure 4. Hydronic Piping — Multiple Boilers, Primary Secondary System.

OPTIONAL PUMP MOUNTED

UNIT AVAILABLE

BOILER CIRC.

PUMP

T1 T1

ADJUSTMENT PROCEDURE TO MAINTAIN 130° F INLET TEMP.

1. Turn on heater and open valves A & B

2. After steady-state operation, if T1 is less than

130° F, slowly close valve B until T1 climbs to 130° F

3. If T1 is greater than 130° F, slowly close valve A until T1 drops to 130° F

4. Check after system operating temperature has stabilized. Make final adjustments

COLD WATER

MAKE-UP

SYSTEM

RETURN

A A

B B B

D

C

D

C

LEGEND

THERMOMETER

TEMPERATURE

SENSOR

GLOBE VALVE

PURGE

VALVE

CHECK VALVE

PRESSURE REDUCING VALVE

W/ FAST FILL BYPASS

EXPANSION TANK

WITH AIR SCOOP AND

AUTO AIR VENT

3-WAY VALVE

VALVE

PUMP

PRIMARY/SECONDARY MANDITORY FOR ALL

VARIABLE FLOW SYSTEMS

INSTALL AIR VENTS AT HIGH POINTS IN SYSTEM

PIPING & SIZING OF EXPANSION TANK

PER TANK MANUFACTURER'S INSTRUCTIONS

DIMENSION ''C'' TO BE 4 PIPE DIAMETERS

DIMENSION ''D'' TO BE 18" MINIMUM

CAUTION: THIS DRAWING SHOWS SUGGESTED

PIPING CONFIGURATION AND VALVING. CHECK

WITH LOCAL CODES AND ORDINANCES FOR

ADDITIONAL REQUIREMENTS.

Figure 5. Hydronic Piping — Multiple Boilers, Low Temperature System.

SYSTEM PUMP

SYSTEM

SUPPLY

BOILER CIRCUIT PIPING MUST BE EQUAL TO

BOILER WATER CONNECTION SIZE

BOILER CIRC. PUMP SIZED FOR FLOW THROUGH BOILER

BOILER CIRC. PUMP TO BE USED WITH EM

SYSTEM TEMP. INTERLOCK REQUIRED

2

DOTTED DEVICES INDICATE ALTERNATE LOCATIONS

MULTIPLE STAGE BOILERS RECOMMENDED

Rheos Boiler and Water Heater

Page 13

Model

Flow

20°F

(Size) gpm

H/L feet

1200

1600

2000

2400

104

139

174

209

18

22

20

18

Flow lpm

395

527

659

791

11°C

Temperature Rise in Degrees (°F/°C)

H/L

m

5.5

6.7

6.1

5.5

Flow gpm

84

111

139

167

25°F

H/L feet

12

14

13

12

14°C

Flow lpm

316

422

527

632

H/L

m

3.7

4.3

4.0

3.7

Flow gpm

70

93

116

139

30°F

H/L feet

8

10

9

8

NOTE: Maximum temperature rise is 30°F (17°C), as shown. Headloss is for boiler’s heat exchanger only.

Table 8. Water Flow Requirements, RHCH (Boiler).

Flow

17°C

lpm

H/L m

264

351

439

527

2.4

3.0

2.7

2.4

OPTIONAL PUMP MOUNTED UNIT AVAILABLE

NOTES:

1. BOILER LOOP TO BE MAINTAINED AT 180° F.

2. ZONE THERMOSTATS TO BE INTERLOCKED WITH BOILER.

BOILER TO FIRE UPON CALL FOR HEAT FROM ANY ZONE.

3. ZONE PIPING AND INTERLOCK WIRING TO BE

DESIGNED BY SYSTEM DESIGNER.

BOILER CIRC.

PUMP

120° F

D

C

C

180° F

C

COLD WATER

MAKE-UP

SYSTEM PUMP

D

C

D

180° F

LEGEND

THERMOMETER

TEMPERATURE

SENSOR

GLOBE VALVE

PURGE

VALVE

CHECK VALVE

PRESSURE REDUCING VALVE

W/ FAST FILL BYPASS

EXPANSION TANK

WITH AIR SCOOP AND

AUTO AIR VENT

3-WAY VALVE

VALVE

PUMP

140° F

PRIMARY/SECONDARY MANDITORY FOR ALL

VARIABLE FLOW SYSTEMS

INSTALL AIR VENTS AT HIGH POINTS IN SYSTEM

PIPING & SIZING OF EXPANSION TANK

PER TANK MANUFACTURER'S INSTRUCTIONS

DIMENSION ''C'' TO BE 4 PIPE DIAMETERS

DIMENSION ''D'' TO BE 18" MINIMUM

CAUTION: THIS DRAWING SHOWS SUGGESTED

PIPING CONFIGURATION AND VALVING. CHECK

WITH LOCAL CODES AND ORDINANCES FOR

ADDITIONAL REQUIREMENTS.

BOILER CIRCUIT PIPING MUST BE EQUAL TO

BOILER WATER CONNECTION SIZE

BOILER CIRC. PUMP SIZED FOR FLOW THROUGH BOILER

BOILER CIRC. PUMP TO BE USED WITH EM

SYSTEM TEMP. INTERLOCK REQUIRED

2

DOTTED DEVICES INDICATE ALTERNATE LOCATIONS

MULTIPLE STAGE BOILERS RECOMMENDED

Figure 6. Hydronic Piping — One Boiler, Multi-Temperature System.

Page 14

OPTIONAL PUMP MOUNTED UNIT AVALIABLE

LAARS Heating Systems

BOILER CIRC.

PUMP

COLD WATER

MAKE-UP

SYSTEM

RETURN

D

LEGEND

THERMOMETER

TEMPERATURE

SENSOR

GLOBE VALVE

PURGE

VALVE

CHECK VALVE

PRESSURE REDUCING VALVE

W/ FAST FILL BYPASS

EXPANSION TANK

WITH AIR SCOOP AND

AUTO AIR VENT

3-WAY VALVE

VALVE

PUMP

Figure 7. Hydronic Piping - Alternate System.

SYSTEM

SUPPLY

C

SYSTEM PUMP

PRIMARY/SECONDARY MANDITORY FOR ALL

VARIABLE FLOW SYSTEMS

INSTALL AIR VENTS AT HIGH POINTS IN SYSTEM

PIPING & SIZING OF EXPANSION TANK

PER TANK MANUFACTURER'S INSTRUCTIONS

DIMENSION ''C'' TO BE 4 PIPE DIAMETERS

DIMENSION ''D'' TO BE 18" MINIMUM

CAUTION: THIS DRAWING SHOWS SUGGESTED

PIPING CONFIGURATION AND VALVING. CHECK

WITH LOCAL CODES AND ORDINANCES FOR

ADDITIONAL REQUIREMENTS.

BOILER CIRCUIT PIPING MUST BE EQUAL TO

BOILER WATER CONNECTION SIZE

BOILER CIRC. PUMP SIZED FOR FLOW THROUGH BOILER

BOILER CIRC. PUMP TO BE USED WITH EM

SYSTEM TEMP. INTERLOCK REQUIRED

2

DOTTED DEVICES INDICATE ALTERNATE LOCATIONS

MULTIPLE STAGE BOILERS RECOMMENDED

PUT BOILER CONTROL SENSOR IN THE OUTLET

WHEN USING THIS PIPING STYLE

BOILER CIRC.

PUMP

OPTIONAL PUMP MOUNTED UNIT AVALIABLE

ADJUSTMENT PROCEDURE TO MAINTAIN 130° F INLET TEMP.

1. Turn on heater and open valves A & B

2. After steady-state operation, if T1 is less than

130° F, slowly close valve B until T1 climbs to 130° F

3. If T 1 is greater than 130° F, slowly close valve A until T1 drops to 130° F

4. Check after system operating temperature has stabilized. Make final adjustments.

COLD WATER

MAKE-UP

A A

B B

SYSTEM

SUPPLY

SYSTEM

RETURN

LEGEND

THERMOMETER

TEMPERATURE

SENSOR

GLOBE VALVE

PURGE

VALVE

CHECK VALVE

PRESSURE REDUCING VALVE

W/ FAST FILL BYPASS

D

EXPANSION TANK

WITH AIR SCOOP AND

AUTO AIR VENT

3-WAY VALVE

VALVE

PUMP

C

SYSTEM PUMP

PRIMARY/SECONDARY MANDITORY FOR ALL

VARIABLE FLOW SYSTEMS

INSTALL AIR VENTS AT HIGH POINTS IN SYSTEM

PIPING & SIZING OF EXPANSION TANK

PER TANK MANUFACTURER'S INSTRUCTIONS

DIMENSION ''C'' TO BE 4 PIPE DIAMETERS

DIMENSION ''D'' TO BE 18" MINIMUM

CAUTION: THIS DRAWING SHOWS SUGGESTED

PIPING CONFIGURATION AND VALVING. CHECK

WITH LOCAL CODES AND ORDINANCES FOR

ADDITIONAL REQUIREMENTS.

BOILER CIRCUIT PIPING MUST BE EQUAL TO

BOILER WATER CONNECTION SIZE

BOILER CIRC. PUMP SIZED FOR FLOW THROUGH BOILER

BOILER CIRC. PUMP TO BE USED WITH EM

SYSTEM TEMP. INTERLOCK REQUIRED

2

DOTTED DEVICES INDICATE ALTERNATE LOCATIONS

MULTIPLE STAGE BOILERS RECOMMENDED

PUT BOILER CONTROL SENSOR IN THE OUTLET

WHEN USING THIS PIPING STYLE

Figure 8. Hydronic Piping - Alternate Low Temperature System.

Rheos Boiler and Water Heater

Page 15

2.3.4 Vertical Combustion Air Terminal

When combustion air is taken from the roof, a field-supplied rain cap or an elbow arrangement must be used to prevent entry of rain water (see Figure 2).

The opening on the end of the terminal must be at least

12" (30cm) above the point at which it penetrates the roof, and high enough above the roof line to prevent blockage from snow. When the vent terminates on the roof, the combustion air must terminate at least 12"

(30cm) below the vent terminal.

2.4 Common Vent Test — Boilers

NOTE: This section does not describe a method for common venting Rheos units. It describes what must be done when a unit is removed from a common vent system. Rheos units require special vent systems and fan for common vent. Contact the factory if you have questions about common venting Rheos units.

When an existing boiler is removed from a common venting system, the common venting system is likely to be too large for proper venting of the appliances remaining connected to it.

At the time of removal of an existing boiler, the following steps shall be followed with each appliance remaining connected to the common venting system placed in operation, while the other appliances remaining connected to the common venting system are not in operation.

1. Seal any unused openings in the common venting system.

2. Visually inspect the venting system for proper size and horizontal pitch and determine there is no blockage or restriction, leakage, corrosion and other deficiencies which could cause an unsafe condition.

3. Insofar as it is practical, close all building doors and windows and all doors between the space in which the appliances remaining connected to the common venting system are located and other spaces of the building. Turn on clothes dryers and any appliance not connected to the common venting system. Turn on any exhaust fans, such as range hoods and bathroom exhausts, so they will operate at maximum speed. Do not operate a summer exhaust fan. Close fireplace dampers.

4. Place in operation the appliance being inspected. Follow the lighting instructions.

Adjust thermostat so appliance will operate continuously.

5. Test for spillage at the draft hood relief opening after 5 minutes of main burner operation. Use the flame of a match or candle, or smoke from a cigarette, cigar or pipe.

6. After it has been determined that each appliance remaining connected to the common venting system properly vents when tested as outlined above, return doors, windows, exhaust fans, fireplace dampers and any other gas burning appliance to their previous conditions of use.

7. Any improper operation of the common venting system should be corrected so that the installation conforms to the National Fuel Gas Code, ANSI

Z223.1/NFPA 54 and/or CSA B149.1, Installation

Codes. When resizing any portion of the common venting system, the common venting system should be resized to approach the minimum size as determined using the appropriate tables in Part

II of the National Fuel Gas Code, ANSI Z223.1

NFPA 54 and/or CSA B149.1, Installation Codes.

SECTION 3.

Gas Supply and Piping

3.1 Gas Supply and Piping

Gas piping should be supported by suitable hangers or floor stands, not the appliance.

Review the following instructions before proceeding with the installation.

1. Verify that the appliance is fitted for the proper type of gas by checking the rating plate. Laars

Heating Systems appliances are normally equipped to operate at elevations up to 2000 feet (610m).

However, the appliance will function properly without the use of high altitude modification at elevations up to 10,000 feet (3050 m).

2. The maximum inlet gas pressure must not exceed

13" W.C. (3.2kPa). The minimum inlet natural gas pressure is 4" W.C. (1.0kPa) and minimum inlet propane gas pressure is 6" (1.5kPa).

3. Refer to Table 7, size supply.

Hard Water Normal Water Soft Water

Model Flow H/L Temp

Flow H/L Temp

Flow H/L Temp

Flow H/L Temp

Flow H/L Temp

Flow H/L Temp

(Size) gpm feet Rise (°F) lpm m Rise (°C) gpm feet Rise (°F) lpm m Rise (°C) gpm feet Rise (°F) lpm

m Rise (°C)

1200

1600

2000

2400

119

161

182

237

20

29

22

23

18

17

19

18

449 6.1

609 8.8

690 6.7

898 7.0

10

10

11

10

93

132

149

186

12

20

15

14

23

21

23

23

351 3.7

500 6.1

565 4.6

703 4.3

13

12

13

13

65

89

6.0

8.9

100 6.6

129 6.9

32

31

35

32

246 1.8

336 2.7

379 2.0

488 2.1

18

17

19

18

Note: Soft Water: 1 to 7.5 grains per gallon

Normal Water: 7.6 to 17 grains per gallon

Hard Water: More than 17 grains per gallon

Note: Headloss is for heater’s heat exchanger only.

Table 9. Water Flow Requirements, RHCV (Water Heater).

Page 16

LAARS Heating Systems

5

1

KEY:

WATER CATEGORY GRAIN

HARDNESS PER GALLON

S = SOFT 1 THROUGH 7.5

N = NORMAL 7.6 THROUGH 17

H = HARD OVER 18

17.1 PARTS PER MILLION

= 1 GRAIN HARDNESS PER GALLON

CAUTION: THIS DRAWING SHOWS SUGGESTED

PIPING CONFIGURATION AND VALVING CHECK

WITH LOCAL CODES AND ORDINANCES FOR

ADDITIONAL REQUIREMENTS

LEGEND

THERMOMETER

EXPANSION TANK

WITH AIR SCOOP AND

AUTO AIR VENT

TEMPERATURE

SENSOR

TPRV

3-WAY VALVE

GLOBE VALVE

PRV

VALVE

CHECK VALVE

PRESSURE REDUCING VALVE

W/ FAST FILL BYPASS

PUMP

Figure 9. Water Heater Piping — One Heater, One Tank.

2

SUPPL

Y

3 4

CWMU

NOTES:

1. OPTIONAL CWMU & RECIRC. LINE LOCATION.

2. WHEN USING INTERMITTENT PUMP AND EM LOCATE REMOTE AQUASTAT

WELL IN LOWER 1/3 OF TANK WITH HEAT SENCEING COMPOUND.

RECIRC.

3. BACK FLOW PREVENTER MAY BE REQUIRED CHECK LOCAL CODES.

4. THERMAL EXPANSION TANK MAY BE REQUIRED CHECK LOCAL CODES.

5. WHEN USING OPTIONAL FACTORY MOUNTED PUMP, MAX PIPE LENGTH

30' TOTAL, 6-90° ELBOWS , FULL PIPE SIZE.

6. THIS DRAWING DEPICTS A TWO-PASS HEAT EXCHANGER.

7. CAUTION: PUMP SIZING MUST BE BASED UPON WATER HARDNESS AT JOB SITE

5

5

3

4

7

CW

MU

KEY:

WATER CATEGORY GRAIN

HARDNESS PER GALLON

S = SOFT 1 THROUGH 7.5

N = NORMAL 7.6 THROUGH 17

H = HARD OVER 18

17.1 PARTS PER MILLION

= 1 GRAIN HARDNESS PER GALLON

CAUTION: THIS DRAWING SHOWS SUGGESTED

PIPING CONFIGURATION AND VALVING CHECK

WITH LOCAL CODES AND ORDINANCES FOR

ADDITIONAL REQUIREMENTS

7

NOTES:

1. OPTIONAL CWMU & RECIRC. LINE LOCATION.

2. WHEN USING INTERMITTENT PUMP AND EM LOCATE REMOTE AQUASTAT

WELL IN LOWER 1/3 OF TANK WITH HEAT SENCEING COMPOUND.

3. BACK FLOW PREVENTER MAY BE REQUIRED CHECK LOCAL CODES.

4. THERMAL EXPANSION TANK MAY BE REQUIRED CHECK LOCAL CODES.

5. WHEN USING OPTIONAL FACTORY MOUNTED PUMP, MAX PIPE LENGTH

30' TOTAL, 6-90° ELBOWS , FULL PIPE SIZE.

6. THIS DRAWING DEPICTS A TWO-PASS HEAT EXCHANGER.

7. COMMON PIPING MUST BE SIZED FOR MAXIMUM COMBINED HEATER FLOW.

8. CAUTION: PUMP SIZING MUST BE BASED UPON WATER HARDNESS AT JOB SITE

Figure 10. Water Heater Piping — Multiple Heaters, One Tank.

CIR

C. R

ETU

RN

SU

PPL

Y

2

LEGEND

THERMOMETER

TEMPERATURE

SENSOR

GLOBE VALVE

TPRV

PRV

CHECK VALVE

PRESSURE REDUCING VALVE

W/ FAST FILL BYPASS

1

EXPANSION TANK

WITH AIR SCOOP AND

AUTO AIR VENT

3-WAY VALVE

VALVE

PUMP

Rheos Boiler and Water Heater

Page 17

5

3

4

CWMU

CIRC.

RETURN

KEY:

WATER CATEGORY GRAIN

HARDNESS PER GALLON

S = SOFT 1 THROUGH 7.5

N = NORMAL 7.6 THROUGH 17

H = HARD OVER 18

17.1 PARTS PER MILLION

= 1 GRAIN HARDNESS PER GALLON

SUPPL

Y

2

CAUTION: THIS DRAWING SHOWS SUGGESTED

PIPING CONFIGURATION AND VALVING CHECK

WITH LOCAL CODES AND ORDINANCES FOR

ADDITIONAL REQUIREMENTS

NOTES:

1. OPTIONAL CWMU & RECIRC. LINE LOCATION.

2. WHEN USING INTERMITTENT PUMP AND EM 2

WELL IN LOWER 1/3 OF TANK WITH HEAT SENCEING COMPOUND.

3. BACK FLOW PREVENTER MAY BE REQUIRED CHECK LOCAL CODES.

4. THERMAL EXPANSION TANK MAY BE REQUIRED CHECK LOCAL CODES.

5. WHEN USING OPTIONAL FACTORY MOUNTED PUMP, MAX PIPE LENGTH

30' TOTAL, 6-90° ELBOWS , FULL PIPE SIZE.

6. THIS DRAWING DEPICTS A TWO-PASS HEAT EXCHANGER.

7. CAUTION: PUMP SIZING MUST BE BASED UPON WATER HARDNESS AT JOB SITE

Figure 11. Water Heater Piping — One Heater, Multiple Tanks.

2

LEGEND

THERMOMETER

TEMPERATURE

SENSOR

GLOBE VALVE

TPRV

PRV

CHECK VALVE

PRESSURE REDUCING VALVE

W/ FAST FILL BYPASS

1

EXPANSION TANK

WITH AIR SCOOP AND

AUTO AIR VENT

3-WAY VALVE

VALVE

PUMP

5

5

7

3

4

CWMU

CIRC.

RETURN

KEY:

WATER CATEGORY GRAIN

HARDNESS PER GALLON

S = SOFT 1 THROUGH 7.5

N = NORMAL 7.6 THROUGH 17

H = HARD OVER 18

17.1 PARTS PER MILLION

= 1 GRAIN HARDNESS PER GALLON

7

SUPPL

Y

CAUTION: THIS DRAWING SHOWS SUGGESTED

PIPING CONFIGURATION AND VALVING CHECK

WITH LOCAL CODES AND ORDINANCES FOR

ADDITIONAL REQUIREMENTS

NOTES:

1. OPTIONAL CWMU & RECIRC. LINE LOCATION.

2. WHEN USING INTERMITTENT PUMP AND EM LOCATE REMOTE AQUASTAT

WELL IN LOWER 1/3 OF TANK WITH HEAT SENCEING COMPOUND.

3. BACK FLOW PREVENTER MAY BE REQUIRED CHECK LOCAL CODES.

4. THERMAL EXPANSION TANK MAY BE REQUIRED CHECK LOCAL CODES.

5. WHEN USING OPTIONAL FACTORY MOUNTED PUMP, MAX PIPE LENGTH

30' TOTAL, 6-90° ELBOWS , FULL PIPE SIZE.

6. THIS DRAWING DEPICTS A TWO-PASS HEAT EXCHANGER.

7. COMMON PIPING MUST BE SIZED FOR MAXIMUM COMBINED HEATER FLOW.

8. CAUTION: PUMP SIZING MUST BE BASED UPON WATER HARDNESS AT JOB SITE

Figure 12. Water Heater Piping — Multiple Heaters, Multiple Tanks.

2

2

LEGEND

THERMOMETER

TEMPERATURE

SENSOR

GLOBE VALVE

TPRV

PRV

CHECK VALVE

PRESSURE REDUCING VALVE

W/ FAST FILL BYPASS

1

EXPANSION TANK

WITH AIR SCOOP AND

AUTO AIR VENT

3-WAY VALVE

VALVE

PUMP

Page 18

4. Run gas supply line in accordance with all applicable codes.

Note: If you have a boiler/water heater with a normally open vent valve, install a vent line from the vent valve to an outside location as required by your installation code or IRI requirement. Do

not remove 3/4 inch pipe plug from the vent valve if venting from the normally open vent valve is not required by your installation code.

5. Locate and install manual shutoff valves in accordance with state and local requirements.

6. A sediment trap must be provided upstream of the gas controls.

7. All threaded joints should be coated with piping compound resistant to action of liquefied petroleum gas.

8. The appliance and its individual shutoff valve must be disconnected from the gas supply piping during any pressure testing of that system at test pressures in excess of 1/2 PSIG (3.45kpa).

9. The unit must be isolated from the gas supply system by closing its individual manual shutoff valve during any pressure testing of the gas supply piping system at test pressures equal to or less than 1/2 PSIG (3.45kpa).

10. The appliance and its gas connection must be leak tested before placing it in operation.

11. Purge all air from gas lines.

WARNING:

Open flame can cause gas to ignite and result in property damage, severe injury, or loss of life.

NOTE: The Rheos appliance and all other gas appliances sharing the gas supply line must be firing at maximum capacity to properly measure the inlet supply pressure. The pressure can be measured at the supply pressure port on the gas valve. Low gas pressure could be an indication of an undersized gas meter, undersized gas supply lines and/or an obstructed gas supply line. A bleed line from the diaphragm-type automatic valve shall be vented per local code requirements. Rheos units are equipped with low and high gas pressure switches that are integrally vent limited. These types of devices do not require venting to atmosphere.

SECTION 4A.

Water Connections — Rheos Boiler

4A.1 Heating System Piping:

Hot Supply Connections — Boiler

LAARS Heating Systems

NOTE: This appliance must be installed in a closed pressure system with a minimum of 12 psi (82.7kPa) static pressure at the boiler.

Hot water piping should be supported by suitable hangers or floor stands. Do not support piping with this appliance. Due to expansion and contraction of copper pipe, consideration should be given to the type of hangers used. Rigid hangers may transmit noise through the system resulting from the piping sliding in the hangers. It is recommended that padding be used when rigid hangers are installed. Maintain 1" (2.5cm) clearance to combustibles for hot water pipes.

Pipe the discharge of the relief valve (full size) to a drain or in a manner to prevent injury in the event of pressure relief. Install an air purger, an air vent, a diaphragm-type expansion tank, and a hydronic flow check in the system supply loop. Minimum fill pressure must be 12psig (82.7kPa). Install shutoff valves where required by code.

Suggested piping diagrams are shown in Figures

4, 5, 6, 7 and 8. These diagrams are meant only as a guide. Components required by local codes must be properly installed.

4A.2 Cold Water Make-Up — Boiler

1. Connect the cold water supply to the inlet connection of an automatic fill valve.

2. Install a suitable back flow preventer between the automatic fill valve and the cold water supply.

3. Install shut off valves where required.

NOTE: The boiler, when used in connection with a refrigeration system, must be installed so the chilled medium is piped in parallel with the boiler with appropriate valves to prevent the chilled medium from entering the boiler.

The boiler piping system of a hot water heating boiler connected to heating coils located in air handling appliances where they may be exposed to refrigerated air circulation must be equipped with flow control valves or other automatic means to prevent gravity circulation of the boiler water during the cooling cycle.

A boiler installed above radiation level, or as required by the authority having jurisdiction, must be provided with a low water cutoff device either as a part of the boiler or at the time of boiler installation.

4A.3 Water Flow Requirements — Boiler

A hydronic heating (closed loop) application recirculates the same fluid in the piping system. As a result, no new minerals or oxygen is introduced into the system. To ensure a proper operating temperature leading to long boiler life, a flow rate has been established based on the fluid temperature rise for this specific size boiler.

Pump-mounted boilers can be ordered for use in primary secondary piping systems. The pumps used are sized for the headloss through the heater, plus 30

Rheos Boiler and Water Heater

Page 19

24V

COM

VDC

SEN

Setpoint Adjustment

Dial

Module

Connector

Increase the head loss requirement by 20%.

IMPORTANT NOTES: Different glycol products may provide varying degrees of protection. Glycol products must be maintained properly in a heating system, or they may become ineffective. Consult the glycol specifications, or the glycol manufacturer, for information about specific products, maintenance of solutions, and set up according to your particular conditions.

Differential

Adjustment

Relay

Energized

LED Indicator

Relay

Heating

Cooling

Note: Jumper must be in “Heating” mode, or Rheos will not operate properly.

Figure 13. Temperature Control.

feet (9.1m) of full-sized piping and a normal number of fittings.

Table 8 specifies water flow rates for boilers, which will enable the user to size a pump. The headloss shown is for the heater only, and the user will need to add the headloss of the system piping to properly size the pump.

The minimum inlet water temperature for the

Rheos is 130°F (54°C) to avoid condensing on the copper coils.

4A.4 Freeze Protection – Boiler

Proper precautions for freeze protection are recommended for boiler installations in areas where the danger of freezing exists.

Power outage, interruption of gas supply, failure of system components, activation of safety devices, etc., may prevent a boiler from firing. Any time a

boiler is subjected to freezing conditions, and the boiler is not able to fire, and/or the water is not able to circulate, there is a risk of freezing in the boiler

or in the pipes in the system. When water freezes, it expands. This can result in bursting of pipes in the system, or damage to the boiler, which could result in leaking or flooding conditions.

Do not use automotive anti-freeze. Maintaining a mixture of minimum 50% water and maximum

50% properly inhibited HVAC glycol, which contains an antifoamant, is the preferred method of freeze protection for Rheos boilers. Percentage of glycol

used in the Rheos boiler must not exceed 50%.

Typically, this mixture will serve as burst protection for temperatures down to approximately –35°F (-

30°C). To get the desired temperature rise across the boiler when this mixture is used, increase the water flow by 15% above the original recommendation.

SECTION 4B.

Water Connections —

Rheos Water Heater

4B.1 Water System Piping —

Water Heater

Hot water piping should be supported by suitable hangers or floor stands. Do not support piping with this appliance. Due to expansion and contraction of copper pipe, consideration should be given to the type of hangers used. Rigid hangers may transmit noise through the system resulting from the piping sliding in the hangers. It is recommended that padding be used when rigid hangers are installed.

The Rheos can be used with several different types of readily available storage tanks. A pump draws water from the storage tank and pumps the water through the heater and back into the tank. Pumpmounted units have a circulating pump built into the water heater.

Pipe the outlet from the heater’s relief valve such that any discharge from the relief valve will be conducted to a suitable place for disposal when relief occurs. Do not reduce line size or install any valves in this line. The line must be installed to allow complete drainage of both the valve and the line.

Suggested piping diagrams are shown in Figures

9, 10, 11 and 12. These diagrams are meant only as a guide. Components required by local codes must be properly installed.

The minimum inlet water temperature for the

Rheos is 130°F (54°C) to avoid condensing on the copper coils.

4B.2 Hot Water Supply Piping —

Water Heater

Follow the tank manufacturer’s guidelines for completion of the hot water system connections.

Page 20

LAARS Heating Systems

NOTE: A listed temperature and pressure relief valve listed as complying with the Standard for

Relief Valves and Automatic Gas Shutoff Devices for Hot Water Supply Systems, 1). ANSI Z21.22 latest edition, or 2). CSA 4.4, of suitable discharge capacity must be installed in the separate storage tank system.

If the Rheos water heater is installed in a closed water supply system, such as one having a backflow preventer in the cold water supply line, the relief valve may discharge periodically, due to thermal expansion.

Means (such as a properly-sized expansion tank) shall be provided to control thermal expansion. Contact the water supplier or local plumbing inspector on how to control this situation.

4B.3 Water Flow Requirements —

Water Heater

In a water heating application (an open system), new water is constantly being introduced. With the new water comes a fresh supply of minerals that can be deposited on the unit’s heat exchanger. This is commonly known as scaling. The amount of minerals will depend upon the hardness of the water. Water can also be aggressive, and can erode metals, including copper, if the water is moved too quickly. The water flow requirements for the Rheos water heater are based upon the hardness of the water. The water flow is kept high enough to prevent scaling, but low enough to prevent tube erosion. For extremely soft or hard water, cupro-nickel tubes are available. Contact a Laars

Representative if you have questions or concerns about water quality.

Pump-mounted water heaters can be ordered with standard pumps for soft or normal water or with pumps for hard water. The pumps used are sized for the headloss through the heater, plus 30 feet (9.1m) of full-sized piping and a normal number of fittings.

Table 9 specifies water flow rates for water heaters, which will enable the user to size a pump.

The headloss shown is for the heater only, and the user will need to add the headloss of the piping system to properly size the pump.

4B.4 Combined Water (potable) Heating and Space Heating

NOTE: These systems are not allowed in the

Commonwealth of Massachusetts.

Piping and components connected to this water heater for the space heating application shall be suitable for use with potable water.

Toxic chemicals, such as used for boiler treatment, shall not be introduced into the potable water used for space heating.

This water heater when used to supply potable water shall not be connected to any heating system

Integration

DIP Switch is set to

“Medium” at the factory.

See Section

5.5.6 for descriptions of other settings.

LED Indicator

(Percent of

Output)

THROT

RANGE

MIN

OUTPUT

OFFSET

V C I

Reverse

Acting

Direct

Acting

Operation Mode

Jumper Positions

Note: Jumper must be in “Reverse Acting” mode, or Rheos will not operate properly.

Figure 14. Proportional Control.

or component(s) previously used with a non-potable water heating appliance.

When the system requires water for heating at temperatures higher than required for other uses, an anti-scald mixing or tempering valve shall be installed to temper the water for those uses in order to reduce scald hazard potential.

4B.5 Freeze Protection – Water Heater

Although Rheos water heaters are designcertified for outdoor installations, such installations are not recommended in areas subject to freezing temperatures unless proper precautions are taken.

Power outage, interruption of gas supply, failure of system components, activation of safety devices, etc., may prevent a heater from firing. Any time a

heater is subjected to freezing conditions, and the heater is not able to fire, and/or the water is not able to circulate, there is a risk of freezing in the

heater or in the pipes in the system. When water freezes, it expands. This can result in bursting of pipes in the system, or damage to the heater, which could result in leaking or flooding conditions.

Rheos Boiler and Water Heater

SECTION 5.

Electrical Connections

WARNING

The appliance must be electrically grounded in accordance with the requirements of the authority having jurisdiction or, in the absence of such requirements, with the latest edition of the National

Electrical Code, ANSI/NFPA 70, in the U.S. and with latest edition of CSA C22.1 Canadian Electrical

Code, Part 1, in Canada. Do not rely on the gas or water piping to ground the metal parts of the boiler. Plastic pipe or dielectric unions may isolate the boiler electrically. Service and maintenance personnel, who work on or around the boiler, may be standing on wet floors and could be electrocuted by an ungrounded boiler. Electrocution can result in severe injury or death.

Single pole switches, including those of safety controls and protective devices must not be wired in a grounded line.

All electrical connections are made in the field wiring box that is located inside the appliance.

NOTE: All internal electrical components have been prewired. No attempt should be made to connect electrical wires to any other location except the wiring box.

Wiring connections are shown in Figures 18 through 33.

5.1 Main Power

Connect a properly sized and fused, 120-volt supply to the main power switch (hot leg is connected directly to switch). Neutral leg is connected directly to the white wire. Ground wire can be connected to the grounding screw in the box or on the switch.

5.2 Pump Connections

The pump time delay relay will call the pump to be energized upon a call for heat, and will keep the pump energized for a delay period after the call for heat has ended. The delay period is adjustable from

0.1 to 10 minutes.

Pump-mounted Rheos units have pumps that are wired at the factory to the pump time delay through a relay. Wiring to a separate 230V single phase circuit, per the wiring diagrams in Figures 18 through 33 is necessary.

Rheos units without the factory-mounted pump also have the pump time delay relay. A 120V single phase pump, which is no larger than 1hP, or 230V single phase pump no higher than 3/4hP, can be wired directly to pump time delay relay, as shown in the unit’s wiring diagram (120V hot connection on the pump to terminal 2 on the pump delay relay, and 120V

Page 21 neutral to the 120V neutral circuit of the unit.)

If the pump is 3-phase, higher voltage than 120V, or higher horsepower than 1hP, the pump’s starter or a separate relay can be connected to the unit’s pump time delay relay, and the pump can be driven indirectly.

Contact the factory if there are questions about connecting a pump to the Rheos’ pump time delay relay.

5.3 Temperature Control — Boiler

Connect boiler T-T wires to isolated contacts on zone valves, circulator relays, sequencing controls

(multiple appliance applications) or other temperature controlled devices. The Rheos boiler temperature control measures temperature on the boiler inlet. Set the temperature control such that the setpoint plus the boiler temperature rise equals the desired boiler outlet temperature. Also set the manual reset high limit

20°F above the outlet temperature to avoid nuisance lockouts.

Example, Imperial units: If the desired outlet temperature is 180°F, and the boiler temperature rise is

25°F, then set the boiler temperature at 155°F (180°F

– 25°F). Lastly, set the manual reset high limit to

200°F (180°F + 20°F).

Example, Metric units: If the desired outlet temperature is 82°C, and the boiler temperature rise is

14°C, then set the boiler temperature at 68°C (82°C-

14°C). Lastly, set the manual reset high limit to 93°C

(82°C+11°C).

5.4 Temperature Control — Water Heater

5.4.1 Remote Water Heater

Temperature Control

The Rheos water heater can be used with a fieldsupplied tank aquastat, sequencing control, or other temperature control device, which will call the unit for heat when the temperature goes below the controller’s setpoint. For the most efficient setting, set the tank temperature at the lowest possible setting for adequate hot water in the application.

Caution

If the tank temperature control is set too high, a potential for hot water scalding may exist.

After a setting has been chosen for the tank temperature control, set the heater temperature control

10°F (6°C) higher. The heater’s temperature control senses the inlet water temperature to the heater. The heater’s manual reset high limit senses heater outlet temperature, and should be set 20°F (11°C) above the outlet temperature to avoid nuisance lockouts.

Example, Imperial units: If the tank temperature is set to 140°F, set the heater’s temperature control to

150°F (140°F+10°F). Further, if the temperature rise

Page 22

LAARS Heating Systems

through the heater is 25°F, the outlet temperature will be 175°F (150°F+25°F). Therefore, set the manual reset high limit to 195°F (175°F + 20°F).

Example, Metric units: If the tank temperature is set to 60°C, set the heater’s temperature control to

66°C (60°C+6°C). Further, if the temperature rise through the heater is 15°C, the outlet temperature will be 81°C (66°C+15°C). Therefore, set the manual reset high limit to 92°C (81°C+11°C).

5.4.2 Internal Water Heater

Temperature Control

When an external control is not used, the circulator between the heater and the storage tank must run continuously, so that the heater’s temperature control can detect and control the water temperature in the storage tank. The Rheos water heater’s temperature control is adjusted to its lowest temperature position when shipped from the factory. This is the preferred starting point for setting the temperature control. Set the manual reset high limit 20°F (11°C) plus heater temperature rise above the temperature control’s setting.

Example, Imperial units: If the heater’s temperature control is set to 130°F, and the temperature rise through the heater is 25°F, the outlet temperature will be 155°F. Set the manual reset high limit to 175°F.

Example, Metric units: If the heater’s temperature control is set to 55°C, and the temperature rise through the heater is 14°C, the outlet temperature will be 69°C. Set the manual reset high limit to 80°C.

Caution

Should overheating occur or the gas supply fail to shut off, turn off the manual gas control valve to the appliance.

5.5 Temperature Control Features

The Rheos temperature control is versatile and will allow the user to better match the modulating control to the application. Settings that can be changed are temperature setpoint, differential, offset, throttling range, and minimum output.

The temperature setpoint is the setting at which the unit will shut off, having satisfied the controller’s call for heat.

The differential determines how far the temperature in the Rheos can fall before energizing again.

The offset determines where the throttling range begins.

The throttling range is the temperature range through which the unit will modulate from minimum to maximum firing rate.

Important Note: These control parameters work together. Therefore, setting one parameter may have an affect on another. Figures 15, 16 and 17 show the relationships between these settings. Figure 15 follows the examples that are shown in the following sections, and Figures 16 and 17 are examples of how the parameters can interfere with each other.

Figure 15. Control Parameter Graph.

Rheos Boiler and Water Heater

Page 23

Figure 16. Control Parameter Possible Interference.

Figure 17. Control Parameter Possible Interference.

Page 24

LAARS Heating Systems

5.5.1 Temperature Setpoint

The temperature setpoint is the point at which the temperature control relay will be de-energized and the unit’s call for heat will end. The temperature setpoint is adjusted with the setpoint dial on the A350 control

(see Figure 13). The temperature control’s sensor is in the inlet of the unit.

5.5.2 Differential Setting

The differential is the difference in temperature settings when the temperature control’s relay is energized and de-energized. For instance, if the temperature setpoint is 180°F (82°C) and the differential is 20°F (11°C), the temperature control will call the unit to energize at 160°F (71°C). (The differential is the setpoint minus the differential setting) The call for heat will end when the unit reaches its setpoint of 180°F (82°C). The Rheos differential is adjustable from 1°F to 30°F (1°C to

17°C). In general, the differential setting for a water heater system will be low, so that when a storage tank is drawing down, the heater will react to sustain a minimum tank temperature. Boilers generally have higher differentials than water heaters, to minimize short cycling (see throttling range). The differential is set by removing the cover of the A350 control and adjusting the potentiometer marked “DIFF” (see

Figure 13).

5.5.3 Offset

The offset determines the temperature below the controller’s setpoint where the throttling range begins.

It offsets the throttling range.

For instance, if the setpoint is 180°F (82°C) and the offset is 5°F (3°C), then the unit’s throttling range will begin at 175°F (79°C). Between 175°F (79°C) and

180°F (82°C), the Rheos will be in low fire.

The offset can be adjusted between 0°F and 30°F

(0°C and 17°C) by removing the cover of the S350P control and adjusting the Offset dial (see Figure 14).

5.5.4 Throttling Range

The throttling range allows the Rheos to match the BTU demands of varying systems, by allowing the user to choose the temperature range through which the unit will modulate. This will tell the controller how fast to respond to a change in temperature. A small throttling range keeps the unit in high fire more, and quickens the response of the system. A larger throttling range allows the Rheos to spread its modulating range over a larger temperature range.

Example, Imperial units: Using a temperature setpoint of 180°F, with a 20°F differential, a 5°F offset, and a throttling range of 10°F, the unit will come on at 160°F and shut off at 180°F. The offset will set the top of the throttling range 5°F under the setpoint, which is 175°F in this example. Therefore, the throttling range will cause the Rheos to modulate between 50% and 100% of full fire between 175°F and

165°F. Between 175°F and 180°F, the unit will remain at low fire. Between 160°F and 165°F, the unit will be at full fire.

Example, Metric units: Using a temperature setpoint of 82°C, with a 11°C differential, a 3°C offset, and a throttling range of 5°C, the unit will come on at

71°C and shut off at 82°C. The offset will set the top of the throttling range 3°C under the setpoint, which is

79°C in this example. Therefore, the throttling range will cause the Rheos to modulate between 50% and

100% of full fire between 79°C and 74°C. Between

79°C and 82°C, the unit will remain at l02 fire.

Between 71°C and 74°C, the unit will be a t full fire.

The throttling range is adjustable between 2°F and 30°F (1°C to 17°C). The range can be set by removing the cover of the S350P control and adjusting the “THROT RANGE” dial (see Figure 14).

5.5.5 Minimum Output Setting

The minimum output setting of the controller is

0% of full fire. However, the minimum output of the

Rheos is limited to 50% of full fire by the fan speed controller, to ensure proper operation of the Rheos.

If a minimum desired output is higher than 50%, the setting can be adjusted up by removing the cover of the S350P control and adjusting the Min Output dial

(see Figure 14). Turning the dial clockwise increases the minimum output. In most cases, this setting should be left as shipped from the factory, with the arrow pointing to the 5 o'clock position.

5.5.6 Integration Constant

The proportional control used on the Rheos has internal circuitry that helps to minimize overshoot that can sometimes be associated with proportional plus integral (PI) controls. There are three field-selectable integration constants (slow, medium and fast), and an off position on the proportional control, which are selected with the dipswitches on the control (see

Figure 14). In most cases, this setting will not need to be changed

Off: Switch 1 to ON position and all others to

OFF. Setting the control to the “Off” position puts the control into proportional only operation. This is not a recommended setting for the Rheos.

Slow: Switch 2 to ON position and all others to OFF. This is the slowest integration constant. It allows the Rheos the most time to reach its setpoint.

In most cases, this is too slow for Rheos installations.

Medium: Switch 3 to ON position and all others to OFF. The integration constant is set to “Medium” at the factory, and in most cases, will not need to be changed. This setting will be the best suited to most

Rheos installations.

Fast: Switch 4 to ON position and all others to OFF. If the rate of system recovery to setpoint is

Rheos Boiler and Water Heater

Page 25 sluggish with the control set to medium, the “Fast” setting may be an improvement. The “Fast” setting will only be used when the rate of change at the sensor is very rapid. In most cases, this setting is too fast for the Rheos.

5.6 External Control Connections

Rheos units are built with a selector switch and a terminal strip to allow the Rheos to receive a 0-

10VDC signal from an external controller (such as a building automation system or multiple boiler control).

When the selector switch is in the “Rheos

Control” position, the Rheos will be modulated by the unit’s factory-mounted modulating control.

When the switch is in the “External Control” position, the unit look for a 0-10VDC signal from an external (field-supplied) controller.

To interlock the external boiler control with the

Rheos, the call for heat signal MUST be connected to the field interlock terminal strip on the Rheos (shown in Figure 18). Be sure to remove the factory-installed jumper between the field interlock terminals. The

0-10VDC modulating signal MUST be connected to external control terminal strip, located to the right of, and behind the front panel. The terminal strip is labeled “0-10VDC +” and 0-10VDC –” to indicate which terminal received the hot signal (+) and which terminal receives the common signal (-) from the controller.

The Rheos unit will modulate between 4.7V and

10V (for 50% and 100%, respectively). Anything less than 4.7 volts will result in 50% of full fire.

For the external control to modulate the Rheos, the selector switch on the front panel must be in the

“External Control” position.

Important Note: DO NOT MAKE/BREAK RHEOS

LINE VOLTAGE TO SIGNAL CALL FOR HEAT. A“call for heat / end call for heat” MUST be connected to the field interlock terminals. The Rheos does not recognize

0 volts as a signal to shut off. If the call for heat is not connected between the field interlock terminals, the

Rheos will remain in low fire when it sees 0 volts as a modulating signal.

Caution

Rheos supply voltage must not be disengaged, except for service or isolation, or unless otherwise instructed by procedures outlined in this manual. To signal a call for heat, use the 24V field-interlock, as shown in the wiring diagram(s).

Some Rheos components are designed to have constant voltage during normal operation. If Rheos supply voltage is toggled as a call for heat signal, premature failure of these components may result.

5.7 Wiring Diagrams

Caution

Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous operation. Verify proper operation after servicing

Page 26

LAARS Heating Systems

Figure 18. Wiring Diagram, Model 1200, Standard and Codes A, C, D, F and G.

Rheos Boiler and Water Heater

Page 27

Figure 19. Wiring Diagram, Models 1600, 2000 and 2400, Standard and Codes A, C, D, F and G.

Page 28

LAARS Heating Systems

Figure 20. Wiring Diagram, Model 1200, Codes B and E.

Rheos Boiler and Water Heater

Page 29

Figure 21. Wiring Diagram, Models 1600, 2000 and 2400, Codes B and E.

Page 30

LAARS Heating Systems

Figure 22. Wiring Diagram, Model 1200, Pump-Mounted, Standard and Codes A, C, D, F and G.

Rheos Boiler and Water Heater

Page 31

Figure 23. Wiring Diagram, Models 1600, 2000 and 2400, Pump-Mounted, Standard and Codes A, C, D, F and G.

Page 32

LAARS Heating Systems

Figure 24. Wiring Diagram, Model 1200, Pump-Mounted, Codes B and E.

Rheos Boiler and Water Heater

Page 33

Figure 25. Wiring Diagram, Models 1600, 2000 and 2400, Pump-Mounted, Codes B and E.

Page 34

Schematic Wiring Diagram

LAARS Heating Systems

Schematic Wiring Diagram

Figure 26. Wiring Schematic, Model 1200, Standard and

Codes A, C, D, F and G.

Figure 27. Wiring Schematic, Models 1600, 2000 and

2400, Standard and Codes A, C, D, F and G.

Rheos Boiler and Water Heater

Schematic Wiring Diagram

Schematic Wiring Diagram

Page 35

Figure 28. Wiring Schematic, Model 1200, Codes B and E.

Figure 29. Wiring Schematic, Models 1600, 2000 and

2400, Codes B and E.

Page 36

Schematic Wiring Diagram

LAARS Heating Systems

Schematic Wiring Diagram

Figure 30. Wiring Schematic, Model 1200, Pump-Mounted, Standard and Codes A, C, D, F and G.

Figure 31. Wiring Schematic, Models 1600, 2000 and

2400, Pump-Mounted Standard and Codes A, C, D, F and G.

Rheos Boiler and Water Heater

Schematic Wiring Diagram Schematic Wiring Diagram

Page 37

Figure 32. Wiring Schematic, Model 1200, Pump-Mounted, Codes B and E.

Figure 33. Wiring Schematic, Models 1600, 2000 and

2400, Pump-Mounted Codes B and E.

Page 38

LAARS Heating Systems

SECTION 6.

Operating Instructions

6.1 Filling the Boiler System

1. Ensure the system is fully connected. Close all bleeding devices and open make-up water valve.

Allow system to fill slowly.

2. If make-up water pump is employed, adjust pressure switch on pumping system to provide a minimum of 12 psi (81.8 kPa) at the highest point in the heating loop.

3. If a water pressure regulator is provided on the make-up water line, adjust the pressure regulator to provide at least 12 psi (81.8 kPa) at the highest point in the heating loop.

4. Open bleeding devices on all radiation units at the high points in the piping throughout the system, unless automatic air bleeders are provided at such points.

5. Run system circulating pump for a minimum of

30 minutes with the boiler shut off.

6. Open all strainers in the circulating system, check flow switch operation, and check for debris. If debris is present, clean out to ensure proper circulation.

7. Recheck all air bleeders as described in Step 4.

8. Check liquid level in expansion tank. With the system full of water and under normal operating pressure, the level of water in the expansion tank should not exceed ¼ of the total, with the balance filled with air.

9. Start up boiler according the procedure in this manual. Operate the entire system, including the pump, boiler, and radiation units for one (1) hour.

10. Recheck the water level in the expansion tank. If the water level exceeds ¼ of the volume of the expansion tank, open the tank drain, and drain to that level.

11. Shut down the entire system and vent all radiation units and high points in the system piping, as described in Step 4.

12. Close make-up water valve and check strainer in pressure reducing valve for sediment or debris from the make-up water line. Reopen make-up water valve.

13. Check gauge for correct water pressure and also check water level in the system. If the height indicated above the boiler insures that water is at the highest point in the circulating loop, then the system is ready for operation.

14. Refer to local codes and the make-up water valve manufacturer’s instructions as to whether the make-up water valve should be left open or closed.

15. After placing the unit in operation, the ignition system safety shutoff device must be tested. First, shut off the manual gas valve, and call the unit for heat. Main gas terminals will be energized, attempting to light, for seven (7) seconds, and then will de-energize. The unit will go into lockout mode. Second, turn the power off, press the manual reset button shown in detail A of

Figure 30, open the manual gas valve and allow the unit to light. While the unit is operating, close the manual gas valve and ensure that power to the main gas valve has been cut.

16. Within three (3) days of start-up, recheck all air bleeders and the expansion tank as described in

Steps 4 and 8 above.

Important: The installer is responsible for identifying to the owner/operator the location of all emergency shutoff devices.

WARNING

Do not use this appliance if any part has been under water. Immediately call a qualified service technician to inspect the appliance and to replace any part of the control system and any gas control that may have been under water.

6.2 Operating the Burner and Set Up

The Rheos modulating appliance utilizes an advanced, state-of-the-art design. The setup must be checked before the unit is put in operation. Problems such as failure to start, rough ignition, strong exhaust odors, etc. can be due to improper setup. Damage to the boiler resulting from improper setup is not covered by the limited warranty.

REQUIRED TOOLS:

Differential pressure gauge capable of reading negative 0.01 inches W.C. (0.002kPa).

1. Using this manual, make sure the installation is complete and fully in compliance with the instructions.

2. Determine that the appliance and system are filled with water and all air has been bled from both. Open all valves.

3. Observe all warnings on the Operating

Instructions label and turn on gas and electrical power to appliance.

4. There is a gas/air test panel to the left of the control panel, at the front of the unit (see Figure

34). Ensure that all four valves on the test panel are closed (see Figure 35).

5. Remove the two plugs from the + and – ports of the air orifice taps, thread hose barbs into the

1/8" NPT connections, and attach the manometer pressure lines to the barbs. Be sure all connections are gas tight.

Rheos Boiler and Water Heater

Figure 34. Gas/Air Test Panel.

Valve

Shown

Closed

Valve

Shown

Open

Page 39

6. Switch on the appliance power switch located on the front of the unit.

7. The Rheos will enter the start sequence. The blower and pump come on for pre-purge, then the ignitor warm-up sequence starts and after all safety devices are verified, the gas valve opens. If ignition doesn’t occur, check that there is proper gas supply. Wait 5 minutes and start the unit again.

8. Open air orifice test port valves. Check air orifice differential at full fire, and make note of the differential.

9. Switch the Rheos off.

10. Close air orifice valves, remove the barbs and replace the plugs. Make sure the connections are gas tight.

11. Remove the two plugs from the + and – ports of the gas orifice taps, thread hose barbs into the

1/8" NPT connections, and attach the manometer pressure lines to the barbs. Be sure all connections are gas tight.

12. Switch on the appliance power switch located on the front of the unit.

13. The Rheos will enter the start sequence. The blower and pump come on for pre-purge, then the ignitor warm-up sequence starts and after all safety devices are verified, the gas valve opens.

14. Open gas orifice test port valves. Check gas orifice differential at full fire, and make note of the differential.

15. Close gas orifice valves, remove the barbs and replace the plugs. Make sure the connections are gas tight.

16. If gas and air orifice differentials match what is shown in Table 10, and do not differ from eachother by more than 0.1" w.c., the unit is properly set up. If not, consult, the factory.

17. After placing the appliance in operation, the

Burner Safety Shutoff Device must be tested.

To test:

(a) Close gas shutoff valve with burner operating.

(b) The flame will go out and blower will continue to run for the post purge cycle.

One additional attempt to light will follow including pre-purge, ignitor on, valve/flame on and post purge. Ignition will not occur as the gas is off. The ignition control will lockout, and will have to be reset before the unit will operate.

(c) Open gas shutoff valve. Restart the appliance. The ignition sequence will start again and the burner will start. The appliance will return to its previous mode of operation.

Figure 35. Test Panel Valves.

Page 40

LAARS Heating Systems

Caution

Should any odor of gas be detected, or if the gas burner does not appear to be functioning in a normal manner, close main shutoff valve, do not shut off switch, and contact your heating contractor, gas company, or factory representative.

Gas Type

Natural

Propane

Air Orifice

Differential

4.0 to 4.5" W.C.

(1.0 to 1.1kPa)

Gas Orifice

Differential

4.0 to 4.5" W.C.

(1.0 to 1.1kPa)

4.5 to 5.0" W.C. 4.5 to 5.0" W.C.

(1.1 to 1.2kPa) (1.1 to 1.2kPa)

Note: Long runs of vent or combustion air piping may reduce the air and gas differential pressures. This is acceptable, as long as the pressures are within 0.1"

(0.025kPa) w.c. of each other.

Table 10. Air and Gas Orifice Differentials at Full Fire.

6.3 Shutting Down the Rheos

1. Switch off the main electrical disconnect switch.

2. Close all manual gas valves.

3. If freezing is anticipated, drain the Rheos and be sure to also protect building piping from freezing.

This step to be performed by a qualified service person.

6.4 To Restart the Rheos

If drained, follow Section 6.1 in this manual for proper filling and purging.

1. Switch off the main electrical disconnect switch.

2. Close all manual gas valves.

3. WAIT FIVE (5) MINUTES.

4. Set the aquastat or thermostat to its lowest setting.

5. Open all manual gas valves.

6. Reset all safety switches (pressure switch, manual reset high limit, etc).

7. Set the temperature controller to the desired temperature setting and switch on electrical power.

8. Burner will go through a prepurge period and ignitor warm-up period, followed by ignition.

SECTION 7.

Maintenance

WARNING

Disconnect all power to the appliance before attempting any service to the appliance. Contact with electricity can result in severe injury or death.

7.1 System Maintenance

1. Lubricate the system water-circulating pump, if required, per the instructions on the pump.

2. If a strainer is employed in a pressure reducing valve or the piping, clean it every six months.

3. Inspect the venting system for obstruction or leakage at least once a year. Periodically clean the screens in the vent terminal and combustion air terminal (when used).

4. Keep the appliance area clear and free from combustible materials, gasoline, and other flammable vapors and liquids.

5. If the appliance is not going to be used for extended periods in locations where freezing normally occurs, it should be isolated from the system and completely drained of all water.

6. Low water cutoffs, if installed, should be checked every 6 months. Float type low water cutoff should be flushed periodically.

7. Inspect and clean the condensate collection and disposal system yearly.

8. When a means is provided to neutralize condensate, ensure that the condensate is being neutralized properly.

9. Inspect flue passages, and clean with brushes/ vacuums, if necessary. Sooting in flue passages indicates improper combustion. Determine the cause and correct.

10. Inspect the vent system and air intake system, and ensure that all joints are sealed properly. If joints need to be resealed, completely remove existing sealing material, and clean with alcohol.

Apply new sealing material, and re-assemble.

7.2 Appliance Maintenance and

Component Description

Only genuine Laars replacement parts should be used.

Caution

Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous operation. Verify proper operation after servicing.

Rheos Boiler and Water Heater

See Figures 36, 37 and 38 for location of gas train and control components.

The gas and electric controls on the appliance are engineered for long life and dependable operation, but the safety of the equipment depends on their proper functioning. It is strongly recommended that a qualified service technician inspect the basic items listed below every year.

a. Ignition control b. Water temperature control c. Automatic gas valve d. Pressure switches e. Blower

7.2.1 Burner

Check the burner for debris. Remove the fan assembly to access the burner. Remove the 6 nuts, which hold the burner in place. Pull burner up and out.

Clean burner, if necessary, by blowing compressed air from the outside of the burner into the center of the burner, and wipe the inside of the burner clean with glass cleaner. A dirty burner may be an indication of improper combustion or dirty combustion air.

Determine the cause, and correct. Always replace the burner gasket when replacing the burner.

7.2.2 Filter

The filter used in the Rheos is washable with an

83% arrestance. Since the filter is washable, it will only need replacement in very rare cases. If filter replacement is needed, it should only be replaced with factory parts. To access the filter, remove the unit’s front panel. Disengage latch on top of filter box and remove the filter box cover. Inspect the air filter. If there is debris on the air filter, remove it from the filter box, and wash it with mild soap and water. Ensure that the filter is completely dry before re-installing, in reverse order.

7.2.3 Modulating Gas Valve

The modulating gas valve consists of a valve body and a pressure regulating electro-hydraulic actuator. It provides the air/gas ratio control for the unit. It is designed to operate with supply pressures of

4-13 inches w.c. (1.0 to 3.2 kPa).

To remove the valve actuator, shut off 120-volt power and the gas shutoff valve. Remove the front panel from the unit. Label the four pressure tubes

that are connected to the valve actuator, to ensure

that they will be replaced correctly. Remove the four tubes from the barb connectors. Disconnect the

110-volt wires from the actuator. Remove the valve actuator by taking out the four screws, and pulling the actuator out. Re-install in reverse order. Turn on gas shutoff valve and 120 volt power and check appliance operation and tightness of gas valve connections.

The gas valve body will rarely have to be removed. If there is a valve problem, and it has been

Page 41 determined the actuator is working properly, the gas valve body may need to be replaced. To remove the gas valve body, shut off 120-volt power and the gas shutoff valve. Remove the front and right-side panels from the unit. Disconnect the union between the valve body and the blower. Label the four pressure

tubes that are connected to the valve actuator, to

ensure that they will replaced correctly. Remove the valve actuator, per the instructions above. Unscrew the valve body from the gas train. After the valve has been removed, replace with a new valve in the reverse order. Turn on gas shutoff valve and 120 volt power and check appliance operation and tightness of gas valve connections.

7.2.4 Safety Gas Valve

The safety gas valve is a 24-volt diaphragm valve. It is designed to operate with supply pressures of 4-14 inches w.c. (1.0 to 3.4 kPa). To remove the gas valve, shut off 120-volt power. Shut off the main gas supply to the unit. Disconnect the gas supply piping from the back of the unit. Disconnect the electrical wires from the valve, and unscrew the gas valve from the gas train. Re-assemble in reverse order. A bleed line from the diaphragm type automatic valve shall be vented per local code requirements.

7.2.5 Manual Reset High Limit Control

The high limit switch is manual reset switch with an adjustable set point, up to 240°F (116°C) on boiler models and 200°F (93°C) water heater models. To replace the switch, shut off the 120-volt power to the appliance. Remove the cover from the switch to access the mounting screws. Remove the screws, and pull the switch off the control panel. Replace in reverse order.

7.2.6 Temperature Control

The temperature control consists of an adjustable electronic control and digital display module. To replace the control or the display, shut off the 120volt power to the appliance. Remove the cover from the control panel, and remove the screws from the

DIN rail clip, to which the controls are mounted. Pull the electrical connector from the controller. Slide the controllers from the DIN rail clip. Replace in reverse order.

7.2.7 Ignition Control

The ignition control ensures the proved interrupted-type ignition system. It controls the hot surface ignitor and proves that the flame signal is appropriate for powering the gas valves. It also controls the blower’s pre-purge and post-purge. To replace the control, shut off the 120-volt power to the appliance. Remove the cover from the control panel.

Remove the electrical connectors from the ignition control. Take out the controller’s mounting screws, and pull the controller out. Replace in reverse order.

Page 42

LAARS Heating Systems

7.2.8 Ignitor / Flame Sensor Assembly

The ignitor is a 110v “Hot Surface” type. It is energized whenever there is a call for heat and switched off when ignition is established and the flame has been sensed. To replace the ignitor, shut off the

120-volt power to the appliance, disconnect the Molex connector, remove the two mounting screws on the ignitor flange, and pull the ignitor out. Always install a new ignitor gasket with the replacement ignitor.

Caution

Ignitor gets hot.

7.2.9 Transformers

There are three transformers in the Rheos unit. One is 24v to 110v, the second is 110v to 24v, and the third is 110v to 220v. Be sure to replace the transformers with factory parts. These transformers are not capable of supplying control voltage for external devices such as zone valves, which must have their own separate power supply. Should a transformer need replacing, shut off the 120-volt power. Unplug the transformer wires, remove the mounting screws and remove the transformer. Replace transformer in the reverse order.

7.2.10 Blower

The combustion air blower is a high-pressure centrifugal blower with a variable speed motor. The speed of the motor is determined by the control logic.

If a blower change is required, turn off the 120-volt power and gas supply to the unit. Take the front panel, the two side access panels, and the top jacket panel off. (If there is enough clearance on the side, the top may not have to be removed.) Disconnect the gas union between the blower and gas valves. Disconnect the filter box assembly (at the air transition) from the blower (six 8 mm bolts). Disconnect the two Molex electrical connectors from the top right of the blower.

Remove the four nuts from the blower flange, and pull the blower out. Replace blower in reverse order, ensuring that all joints are made correctly and sealed.

After replacement, ensure that the unit operates properly, by following the set-up procedure in this manual.

7.2.11 Flow Switch

The Rheos uses a paddle-type flow switch to ensure that the unit has water flow before ignition is allowed.

7.2.12 Heat Exchanger Coil

Black carbon soot buildup on the external surfaces of the heat exchanger is caused by one or more of the following; incomplete combustion, combustion air problems, venting problems and heater short cycling. Soot buildup or other debris on the heat exchanger may restrict the flue passages.

If black carbon soot buildup is suspected, disconnect electrical supply to the unit, and turn off the gas supply by closing the manual gas valve on the unit. Access the heat exchanger through the side access panels, and inspect the finned copper tubing using a flashlight. If there is a buildup of black carbon soot or other debris on the heat exchanger, clean per the following:

Caution

Black carbon soot buildup on a dirty heat exchanger can be ignited by a random spark or flame. To prevent this from happening, dampen the soot deposits with a wet brush or fine water spray before servicing the heat exchanger.

1. Disconnect the electrical supply to the unit.

2. Turn off the gas supply by closing the manual gas valve on the heater.

3. Disconnect and remove the wires, conduit and sensors from all components that are attached to the inlet/outlet header.

4. Isolate the heat exchanger from the water supply.

5. Drain the heat exchanger from the drain located on the bottom of the heat exchanger.

6. Disconnect the header flanges from the inlet and outlet.

7. Remove the heat exchanger from the unit.

NOTE: The heat exchangers are heavy and may require two people to remove to avoid personal injury.

8. Clean the heat exchanger: A light accumulation of soot or corrosion on the outside of the heat exchanger can be easily removed. Use a wire brush to remove loose soot and scale from the heat exchanger. Do not use water or compressed air for cleaning.

9. NOTE: While the heat exchanger is out of the unit, inspect the firewall refractory insulation blocks for cracks, wear and breakage. Replace if necessary.

10. Inspect the inside of the copper tubes for scale buildup. Scale can build up on the inner surface of the heat exchanger tubes, which can restrict water flow. If the tubes show signs of scaling, clean the internal surface. Laars offers a tube cleaning kit part number R2000700.

11. Reassemble in the reverse order.

If heat exchanger removal is necessary, consult the factory for instructions.

NOTE: The Warranty does not cover damage caused by lack of required maintenance, lack of water flow, or improper operating practices.

Rheos Boiler and Water Heater

Air Inlet

Transition

Standard and Control Pack C Gas Train

High Gas

Pressure Switch

Modulating Gas

Valve Actuator

Safety

Gas Valve

Manual

Gas Valve

Pressure

Switch

Gas Orifice

Air Inlet

Transition

Manual

Gas Valve

Modulating Gas

Valve Body

Low Gas

Pressure

Switch

Control Packs A and D Gas Train

High Gas

Pressure Switch

Modulating Gas

Valve Actuator

Normally Open

Vent Valve

Safety

Gas Valve

Page 43

Pressure

Switch

Gas Orifice

Manual

Gas Valve

Figure 36. Gas Trains.

7.2.13 Normally Open Vent Valve

Some Rheos models provide a normally open vent valve for installations with IRI code requirements.

The valve opens when power is removed from the safety valves. And the valve closes when the safety valves are powered. See sections 3.1 Item #4 for installation instructions.

7.2.14 Motorized Safety Valve

Control packs B and E have an additional motorized safety valve. This valve is powered open

Modulating Gas

Valve Body

Manual

Gas Valve

Low Gas

Pressure Switch at the same time as the safety valve. To remove the valve actuator, shut off the 120V power and the gas shutoff valve. Remove the right side, or front panel.

Disconnect the 120V wires from the actuator. Remove the valve actuator by taking out the four screws, and pulling the actuator out. Re-install in reverse order.

Turn on gas shutoff valve and 120V power and check appliance operation and tightness of gas valve connections.

The gas valve body will rarely have to be removed. If there is a valve problem, and it has been

Page 44

LAARS Heating Systems

Control Packs B and E Gas Trains

High Gas

Pressure Switch

Pressure

Differential

Tube Assembly

Modulating Gas

Valve Actuator

On/Off Gas

Valve Actuator

Low Gas

Pressure Switch

Air Inlet

Transition

Manual

Gas Valve

Air Inlet

Transition

Modulating Gas

Valve Actuator

High Gas

Pressure Switch

Pressure

Differential

Tube Assembly

On/Off Gas

Valve Actuator

Low Gas

Pressure Switch

Pressure

Switch

Gas Orifice

Solenoid Safety

Gas Valve

Modulating Gas

Valve Bodies

Pressure

Switch

Gas

Orifice

Modulating Gas

Valve Body

Solenoid Safety

Gas Valve

Manual

Gas Valve

Figure 37. Gas Train.

determined the actuator is working properly, the gas valve body may need to be replaced. To remove the gas valve body, shut off 120V power and the gas shutoff valve. Remove the right side and front panels.

Remove the valve actuator. Unscrew the valve body from the gas train. After the valve has been removed, replace with a new valve in reverse order. Turn on gas shutoff valve and 120V power and check appliance operation and tightness of gas valve connections.

7.2.15 Gas Pressure Switches

The high and low gas pressure switches are 24V manual reset switches that act to cut power to the gas valves if the gas pressure is too low or too high for proper operation. The gas pressure switches used are integrally vent limited, and do not require venting to atmosphere. To remove a switch, remove the screw on the plastic housing and pull the clear cover off.

Disconnect the two wires from the screw terminals.

Twist the switch off the pipe nipple. Reassemble in reverse order. For natural gas, set the low gas pressure switch to 3" w.c. For propane, set the low gas pressure switch to 5" w.c. For natural and propane, set the high gas pressure switch to 14".

Figure 38. Control Panel.

Rheos Boiler and Water Heater

Page 45

SECTION 8.

Trouble Shooting

8.1 Sequence of Operation

The Rheos appliance is a cold start appliance that should start only on a call for heat from a tank aquastat, room thermostat, zone valve end switch or other space temperature control device.

1. Upon a call for heat,

(a) The internal pump will start. (Pump is optionally mounted on unit.)

(b) The blower will begin a 15 second prepurge.

2. Following the prepurge cycle the hot surface ignitor will heat and will begin a 7 second trial for ignition. The unit is allowed three attempts for ignition.

3. The gas valve will then be energized and lowfire (50% of full fire) ignition will occur. The unit will remain in a low-fire start-up period for 15 seconds.

4. After the low-fire start time is over, the unit will be in normal operation firing rate and will modulate based on the heating load via the temperature controller settings and readings.

5. When the call for heat is complete, or the unit reaches its setpoint temperature, the gas valve will close, and the fan will continue to run for its 30 second post-purge. If a pump time delay is used, the pump will continue to run for the specified amount of time (adjustable from 0.1 to

10 minutes).

8.2 Resolving Lockouts

There are many causes of lockouts. The three most common causes are: (1) inadequate gas supply,

(2) poor combustion, (3) ignitor failure (4) combustion air.

1. Inadequate gas supply: Before proceeding, ensure that the gas supply has not been shutoff or the LP tank (LP boilers) is not empty. Then, restart the boiler and observe the operational cycle. After the pre-purge time, the unit should light. If it does not, consult the factory.

2. Poor Combustion: Poor combustion should be suspected if there is a strong flue gas odor. The odor may result from an improper gas/air ratio

(high or low O

2

or CO

2

). If an improper gas/air ratio is suspected, consult the factory.

3. Ignitor failure: If the boiler goes through a normal start cycle but combustion does not occur, ignitor failure should be suspected. Check the ignitor by unplugging the ignitor plug and measuring the ignitor resistance. It should be

50-80 (-) ohms. If the resistance is not 50-80 ohms (W), replace the ignitor. If the resistance is correct, reset the boiler and check for 120 VAC at the ignitor plug during the start cycle. If there is no voltage, replace the faulty ignitor wire harness.

4. Inadequate combustion air: If the boiler goes through a normal ignition cycle, and shuts off after the blower ramps up to full speed, an abnormal restriction in the air intake or exhaust system should be suspected. Check the air filter for buildup of debris and clean filter if necessary.

Inspect all exhaust venting and intake venting for blockages. Remove any blockages and inspect and replace any damaged vent sections. If the unit still continues to lockout after igniting, consult the factory.

Once the reason for the lockout has been identified and resolved you can reset the unit by pressing the manual reset button (see Detail A in

Figure 30. Control Panel).

8.3 Delayed Ignition - Possible Causes

8.3.1 High Lockup Pressure (LP

Appliances) - Occurs on Start-up

High lock up pressure is the most common cause of delayed ignitions on LP fueled appliances. It may result from an improper second stage regulator selection or from a faulty regulator.

Lock up can be detected by measuring the gas supply pressure to the appliance at the inlet pressure port on the gas valve. The gas supply to the appliance must be shut off before making any connections. To check: use a water manometer or pressure gauge with a scale reading of at least 25 in. W.C. or 15 oz/in

2

.

(6.2kPa). Attach the manometer to the gas valve inlet pressure port. Turn on the gas supply. The Rheos appliance is designed to operate with supply pressures of 4-13 in. W.C. (2.3 - 7.5 oz/ in²) (0.1-3.2kPa). If the supply pressure exceeds 13 in. W.C. (7.5 oz/ in²)

(3.2kPa) (with the appliance off) it is possible that this may be the cause of the delayed ignitions and the inlet pressure must be reset to between 4-13 in. W.C. (2.3

2

) (0.1-3.2kPa). Restart the appliance and – 7.5 oz/in then switch it off. If the inlet gas pressure exceeds 13 in. W.C. (7.5 oz/ in²) (3.2kPa) after the appliance is switched off, correct the lock up problem.

8.3.2 Gas Valve Regulation

Gas valve regulation problems can also cause delayed ignitions. If gas valve regulation problems are suspected, consult the factory. Do not attempt field adjustment or repair.

Page 46

LAARS Heating Systems

8.3.3 Defective Burner - Occurs on

Startup or at Burner Shutdown

A defective burner can cause a delayed ignition.

If the gas supply pressure is proper, the gas valve is functioning properly, the burner should be inspected.

There should be no distortion or perforations in the burner. Replace if indicated.

8.4 Short Cycling — Boiler

Because the Rheos is a modulating boiler, and its input will decrease when there is a reduction in heating load, short cycling is greatly reduced. If the heating load drops below the minimum input of the boiler for an extended period, the boiler will have a tendency to short cycle. This can be a symptom of improper control strategy or setpoints, or a load distribution problem. See Section 5.5 regarding controller setup.

Contact your Laars representative to discuss possible remedies.

8.5 Short Cycling — Water Heater

Short cycling will generally occur only in combination space heating and water heating applications when the water heater is operating in the space-heating mode. Because the Rheos is a modulating water heater and its input will reduce when there is a reduction in heating load, short cycling is greatly reduced. If the heating load drops below the minimum input of the water heater for an extended period, the water heater will have a tendency to short cycle. If short cycling is frequently experienced, regardless of the control’s attempt to limit it, the heating load should be redistributed to control it. See

Section 5.5 regarding controller setup.

If short cycling occurs in a water heater application, it is probably caused by undersized piping between the water heater and the storage tank or by some other factor that restricts proper water flow through the water heater. The cause should be determined and corrected.

8.6 High Gas Consumption

Appliances operating with an improper air/fuel ratio are very inefficient and consequently, have very high gas consumption. Because efficiency is high when the CO

2

is high (or O

2

is low), appliances operating with low CO

2

or high O

2

(especially LP appliances) consume more gas. Adjust the CO

2

or O for optimum efficiency. If no combustion analyzing equipment (CO

2

or O

2

) is available then a proper

2 adjustment of the air/fuel ratio (CO

2

or O

2

) can not flue gases it is possible to determine if the CO

2

O

2

or

is within the proper range. No significant flue gas odor should be detected when combustion is proper.

A strong piercing smell indicates poor combustion and generally a lean mixture - low CO

The CO

2

or high O attempt to correct combustion. Contact factory if the

CO

2

is not within this range.

2

.

should be 8 to 9% at all firing rates. Do not

SECTION 9.

Replacement Parts

Only genuine Laars replacement parts should be used.

9.1 General Information

To order or purchase parts for the Laars Rheos, contact your nearest Laars dealer or distributor. If they cannot supply you with what you need, contact

Customer Service (see back cover for address, telephone and FAX numbers).

Rheos Boiler and Water Heater

9.2 Parts List

COMBUSTION COMPONENTS

See Figure 39

1200

1 Combustion chamber assembly

2 Base assembly

3 Panel, front cover, base frame

4 Panel, top, combustion chamber (with insulation)

5 Panel, bottom, combustion chamber

6 Panel, left, combustion chamber

7 Panel, right, combustion chamber

8 Panel, access, combustion chamber

R2010800

R2001100

R2001200

R2001300

R2001400

R2001500

R2001600

R2001700

9 Support, front, fan transition

10 Support, rear, fan transition

11 Hardware kit, combustion chamber

12 Burner, with gaskets

R2010200

R2010300

R2002200

R2013200

13 Gasket kit, burner R2002400

14 Tile kit (top & bottom of heat exchanger w/top insulation) R2002500

15 Tile support w/rods

16 Tile support protective liner

17 Flue collector kit (with gaskets)

18 Gasket kit, flue collector

19 Gasket kit, combustion chamber

20 Heat exchanger assembly, copper

20 Heat exchanger assembly, cupro-nickel

21 Baffle, flue

R2010900

R2016900

R2011000

R2002900

R2003000

R2013300

R2013301

R2017300

GAS TRAIN / COMBUSTION AIR COMPONENTS

See Figures 40 and 41

25 Gas train assembly, standard, Nat

25 Gas train assembly, standard, LP Nat

25 Gas train assembly, control pack A, Nat

25 Gas train assembly, control pack A, LP Nat

25 Gas train assembly, control pack B and E, Nat

25 Gas train assembly, control pack B and E, LP Nat

26 Gas valve, safety

27 Gas valve, solenoid safety, for control packs B & E

28 Gas valve, mod valve actuator

29 Gas valve, mod valve body

29 Gas valve, mod valve body, size 2000, Nat

29 Gas valve, mod valve body, size 2000, LP

30 Gas valve, mod complete (body and actuator)

30 Gas valve, mod complete (body and actuator) size 2000, Nat

30 Gas valve, mod complete (body and actuator) LP gas size 2000, LP

31 Gas valve, manual

32 Double valve body / Actuator

33 Double valve body

34 On/Off Actuator

35 Normally open vent valve

36 Gas orifice kit (orifice in holder), Nat

36 Gas orifice kit (orifice in holder), LP

37 Gas orifice, Nat

37 Gas orifice, LP

38 Pressure switch, high gas

R2011100

R2011200

R2017800

R2018200

R2018600

R2019000

R2011300

R2019400

R2003400

R2011400 not used not used

R2011500 not used not used

R2011600 not used not used

R2019800

R2014400

R2011700

R2011800

R2011900

R2012000

R2004000

Page 47

1600

R2016300

R2001100

R2001200

R2001300

R2001400

R2001500

R2001600

R2001700

R2010200

R2010300

R2002200

R2016500

R2002400

R2002500

R2016700

R2016900

R2011000

R2002900

R2003000

R2017100

R2017101 not used

2000

R2016400

R2001100

R2001200

R2001300

R2001400

R2001500

R2001600

R2001700

R2010200

R2010300

R2002200

R2016600

R2002400

R2002500

R2016800

R2016900

R2017000

R2002900

R2003000

R2017200

R2017201 not used

2400

R2001000

R2001100

R2001200

R2001300

R2001400

R2001500

R2001600

R2001700

R2010200

R2010300

R2002200

R2002300

R2002400

R2002500

R2002600

R2002700

R2002800

R2002900

R2003000

R2003100

R2003101 not used

R2017400

R2017600

R2017900

R2018300

R2018700

R2019100

R2003300

R2019500

R2003400

R2011400 not used not used

R2011500 not used not used

R2003700 not used not used

R2019800

R2014400

R2019900

R2020100

R2020300

R2020500

R2004000

R2017500

R2017700

R2018000

R2018400

R2018800

R2019200

R2003300

R2019500

R2003400 not used

R2003500

R2011400 not used

R2003600

R2011500

R2003700

R2019600

R2019700

R2019800

R2014400

R2020000

R2020200

R2020400

R2020600

R2004000

R2003200

R2010400

R2018100

R2018500

R2018900

R2019300

R2003300

R2019500

R2003400

R2003500 not used not used

R2003600 not used not used

R2003700

R2019600

R2019700

R2019800

R2014400

R2003800

R2010500

R2003900

R2010600

R2004000

Page 48

LAARS Heating Systems

1200

39 Pressure switch, low gas

40 Tubing/Fittings (gas train repair kit)

R2004100

R2020700

41 Air filter box assembly (with gasket and hardware) Nat R2020800

41 Air filter box assembly (with gasket and hardware) LP R2020800

42 Air filter

43 Gasket kit, air filter

44 Air filter box cover

45 Air filter felt gasket

46 Air filter air inlet vent w / gasket

47 Blower

48 Blower gasket kit

49 Air orifice, Nat

50 Air orifice strip, LP

51 Air orifice, LP

52 Air restrictor, LP

53 Air transition (filter box to blower)

54 Blower adapter transition

55 Ignitor kit (with gasket)

56 Sight glass

57 Pressure switch, air

R2004500

R2004600

R2004700

R2004800

R2021300

R2012100

R2012200

R2012300 not used

R2026400

R2026500

R2012500

R2022300

RW2002300

R2005300

R2022400

ELECTRICAL COMPONENTS

See Figure 42

60 Transformer, 115/24V, 40VA step down,

60 Transformer, 115/24V, 80VA step down, for control pack B & E only

62 Transformer, 24/115 step up

63 Fuse kit, 2 Amp, 5 pack (not shown)

63 Fuse kit, 5 Amp, 5 pack (Control packs B and E)

(not shown)

64 Fuse holder (qty of 5)

65 Diagnostic lights kit

66 Ignition control (Single Trial)

66 Ignition control (Three Trial, Control packs F and G)

67 High limit, manual reset, RHCH boiler

67 High limit, manual reset, RHCV water heater

68 Temperature control, RHCH boiler

69 Module, proportional control

70 Relay, DPDT, 24V coil

71 Relay, Time Delay on Make

72 Relay, DPDT, 120V coil

73 Relay, EM2 kit

74 Relay, 115VAC SPST

75 Voltage regulator

76 Terminal block, 2 position

77 Terminal block, 4 position

78 Sensor, temperature control (not shown)

79 Switch, toggle, 3-way SPDT

80 Switch, toggle, DPDT

81 Control signal converter

82 Bell, alarm, 24V

83 Cover, control panel top

84 Cover, control panel bottom

85 Enclosure, control panel

86 Voltage divider panel, Std and control pack options

A, C, and D

86 Voltage divider panel, control pack options B and E

87 Support, control panel bottom

1200

R0021300

R2022500

R2005500

RE2043600

RE2043500

RE2000300

R2005600

R2014100

R2022600

RE0015900

RE2217800

R2005800

R2005900

R2006000

R2006100

R2006200

RE2077700

R2014200

R2006300

R2006400

R2006500

R2006600

R2007700

R2015000

R2012700

R2014200

R2006700

R2007000

R2006800

R2006900

R2015200

R2007100

1600 2000

R2004100

R2020700

R2020900

R2021000

R2004500

R2004600

R2004700

R2004800

R2021400

R2004900

R2005000

R2021500 not used

R2021600

R2022100

R2005200 not used not used

RW2002300 RW2002300

R2005300

R2022400

R2005300

R2022400

R2004100

R2020700

R2004400

R2021100

R2004500

R2004600

R2004700

R2004800

R2021400

R2004900

R2005000

R2021700

R2022000

R2021700

R2022200

R2005200

2400

R2004100

R2020700

R2004400

R2021200

R2004500

R2004600

R2004700

R2004800

R2021400

R2004900

R2005000

R2005100

R2022000

R2005100 not used

R2005200 not used

RW2002300

R2005300

R2022400

1600

R0021300

R2022500

R2005500

RE2043600

RE2043500

RE2000300

R2005600

R2014100

R2022600

RE0015900

RE2217800

R2005800

R2005900

R2006000

R2006100

R2006200

RE2077700

R2014200

R2006300

R2006400

R2006500

R2006600

R2007700

R2015000 not used

R2014200

R2006700

R2007000

R2006800

R2006900

R2015200

R2007100

2000

R0021300

R2022500

R2005500

RE2043600

RE2043500

RE2000300

R2005600

R2014100

R2022600

RE0015900

RE2217800

R2005800

R2005900

R2006000

R2006100

R2006200

RE2077700

R2014200

R2006300

R2006400

R2006500

R2006600

R2007700

R2015000 not used

R2014200

R2006700

R2007000

R2006800

R2006900

R2015200

R2007100

2400

R0021300

R2022500

R2005500

RE2043600

RE2043500

RE2000300

R2005600

R2014100

R2022600

RE0015900

RE2217800

R2005800

R2005900

R2006000

R2006100

R2006200

RE2077700

R2014200

R2006300

R2006400

R2006500

R2006600

R2007700

R2015000 not used

R2014200

R2006700

R2007000

R2006800

R2006900

R2015200

R2007100

Rheos Boiler and Water Heater

88 Panel, diagnostic lights

89 Bracket, mounting, diagnostic panel

90 Standoff

91 Hardware kit, control panel

92 Bracket, support, control panel top

HEAT EXCHANGER / WATER PATH

See Figure 43

93 Header cover

93 Header cover, pump mount

94 Water barrier assembly

95 Gasket kit, heat exchanger cover

96 Hardware kit, heat exchanger cover

97 Gauge, temperature/pressure

98 Pressure relief valve, RHCH boiler

98 Pressure relief valve, RHCV boiler

100 Immersion well, high limit

101 Immersion well, temperature control

102 Tube cleaning kit (not shown)

103 Flow switch (with paddle)

104 Low water cutoff, manual reset

105 Pump, circulator (normal water)

105 Pump, circulator (hard water)

106 Bracket, pump mounting (normal water)

106 Bracket, pump mounting (hard water)

107 Flange, pump, gaskets / hardware

108 Shims, pump bracket (10 ea)

109 Gaskets (10 pk)

110 Temperature switch, bi-metal disc

JACKET

See Figure 44

115 Panel, upper front access

116 Panel, lower front access

117 Panel, waterway access

117 Panel, waterway access, pump

118 Panel, waterway cover

119 Panel, pump access

120 Panel, PRV access

121 Panel, rear access

122 Panel, front left

123 Panel, front right

124 Panel, rear left

125 Panel, rear right

126 Panel, common access

127 Panel, top

128 Panel, support

129 Panel, flue vent access

130 Panel, ducted air cover

131 Jacket trim kit

132 Hardware kit, jacket

133 Window, control / display

134 Window guide

135 Window latch

136 Jacket retro-fit kit (standard)

137 Jacket retro-fit kit (mounted pump)

Page 49

1200

R2007300

R2007400

R2007500

R2007600

R2007800

1600

R2007300

R2007400

R2007500

R2007600

R2007800

2000

R2007300

R2007400

R2007500

R2007600

R2007800

2400

R2007300

R2007400

R2007500

R2007600

R2007800

1600

R2015101

R2015102

R2025100

R2025400

R2025600

R2025800

R2025900

R2008600

R2008700

R2008800

R2008900

R2009000

R2009100

R2009200

R2009300

R2026000

R2009500

R2009600

R2009700

R2009800

R2009900

R2010000

R2026500

R2026900

1600

R2022700

R2023000

R2023300

R2023500

R2023700

RA0079000

A0063600

A0064400

RE2058300

RE2074000

R2000700

R2008400

RE2075100

R2024100

R2024200

R2024500

R2024600

R2024800

R2013600

R2013800

R2024900

1200

R2015101

R2015102

R2025000

R2025400

R2025600

R2025700

R2025900

R2008600

R2008700

R2008800

R2008900

R2009000

R2009100

R2009200

R2009300

R2026000

R2009500

R2009600

R2009700

R2009800

R2009900

R2010000

R2026400

R2026800

1200

R2012800

R2022900

R2012900

R2013000

R2013100

RA0079000

A0063600

A0001200

RE2058300

RE2074000

R2000700

R2008400

RE2075100

R2023900

R2024000

R2024600

R2024600

R2024700

R2013600

R2013800

R2024900

2400

R2015101

R2015102

R2025300

R2025500

R2025600

R2025800

R2025900

R2008600

R2008700

R2008800

R2008900

R2009000

R2009100

R2009200

R2009300

R2026300

R2009500

R2009600

R2009700

R2009800

R2009900

R2010000

R2026700

R2027100

2400

R2007900

R2023200

R2008000

R2008200

R2008300

RA0079000

A0002700

A0000400

RE2058300

RE2074000

R2000700

R2008400

RE2075100

R2024100

R2024200

R2024500

R2024600

R2024800

R2013600

R2013800

R2024900

2000

R2015101

R2015102

R2025200

R2025400

R2025600

R2025800

R2025900

R2008600

R2008700

R2008800

R2008900

R2009000

R2009100

R2009200

R2009300

R2026100

R2009500

R2009600

R2009700

R2009800

R2009900

R2010000

R2026600

R2027000

2000

R2022800

R2023100

R2023400

R2023600

R2023800

RA0079000

A0002700

A0000400

RE2058300

RE2074000

R2000700

R2008400

RE2075100

R2024300

R2024400

R2024500

R2024600

R2024700

R2013600

R2013800

R2024900

Page 50

20

14

19

19

19

6

4

9

12

13

LAARS Heating Systems

10

14

14

14

18 OR 19

18 OR 19

17

14

16

15

21

19 19 5

1 - Complete Combustion

Component Assembly

11 - Hardware Kit,

Combustion Chamber

7

19

19

19

18 OR 19

8

3

2 (ASSEMBLY)

Figure 39. Combustion Components.

Rheos Boiler and Water Heater

51

49

50

41

46

43

44

42

45

48

54

48

48

52

48

55

47

48

56

Page 51

Figure 40. Gas Train/Combustion Air Components.

Page 52

LAARS Heating Systems

53

40

38

28 OR 30

26

31

Standard and

Control Pack C

Gas Train

57

53

36 OR 37

31

29 OR 30

53

39

40

Control Packs

A and D

Gas Train

57

40

38

28 OR 30

34

36 OR 37

27

39

31

31

38

28 OR 30

35

29 OR 30

57

36 OR 37

31

For sizes 1200, 1600 and

2000 Propane gas

29 OR 30

29

53

26

39

31

Control Packs B and E Gas Train

34

27

39

31

40

38

28 OR 32

57

36 OR 37

31

32 OR 33

For sizes 2000 Natural gas and 2400

Figure 41. Gas Train Components.

Rheos Boiler and Water Heater

Page 53

Figure 42. Electrical Components.

Page 54

100

96

93

95

98

107 OR 109

107

LAARS Heating Systems

104

101

106

110

97

94

105

106 OR 108

106

106

106

103

Figure 43. Heat Exchanger / Water Path Components.

Rheos Boiler and Water Heater

133

135

115

126

128

124

134

132 - Jacket Hardware Kit

136 - Jacket Retro-fit Kit (standard)

137 - Jacket Retro-fit Kit (mounted pump)

127

131

128

130

Page 55

120

118

122

126

117

123

119

125

131

121

129

116

Figure 44. Jacket Components.

Page 56

Tables Listing

Table 1

Table 2

Table 3

Table 4

Table 5

Table 6

Table 7

Terminals for Outdoor Installation......................6

Clearances ........................................................6

Vent / Air Pipe Sizes ..........................................7

Horizontal Vent and Air Terminals

For Indoor Installations ......................................9

Required Combustion Air Piping Material..........9

Required Venting Material .................................9

Gas Piping Sizes .............................................10

Table 8

Table 9

Water Flow Requirements – RHCH (Boiler) ....13

Water Flow Requirements – RHCV

(Water Heater) .................................................15

Table 10 Air & Gas Orifice Differentials at Full Fire ........40

Figures Listing

Figure 1 Dimensional Drawing ........................................5

Figure 2 Combustion Air and Vent Through Roof ............7

Figure 3 Combustion Air and Vent Through Side-Wall ....8

Figure 4 Hydronic Piping – Multiple Boilers,

Primary Secondary System .............................12

Figure 5 Hydronic Piping – Multiple Boilers,

Low Temerature System ..................................12

Figure 6 Hydronic Piping – One Boiler,

Multi-Temperature System ..............................13

Figure 7 Hydronic Piping - Alternate System .................14

Figure 8 Hydronic Piping - Alternate Low

Temperature System .......................................14

Figure 9 Water Heater Piping – One Heater, One Tank .... 16

Figure 10 Water Heater Piping – Multiple Heaters,

One Tank .........................................................16

Figure 11 Water Heater Piping – One Heater,

Multiple Tanks ..................................................17

Figure 12 Water Heater Piping – Multiple Heaters,

Multiple Tanks ..................................................17

Figure 13 Temperature Control........................................19

Figure 14 Proprotional Control ........................................20

Figure 15 Control Parameter Graph ................................22

Figure 16 Control Parameter Possible Interference ........23

Figure 17 Control Parameter Possible Interference ........23

Figure 18 Wiring Diagram, Model 1200,

Standard and Codes A, C, E, F and G ............26

LAARS Heating Systems

Figure 19 Wiring Diagram, Models 1600, 2000 and 2400,

Standard and Codes A, C,E, F and G .............27

Figure 20 Wiring Diagram Model 1200,

Codes B and E ................................................28

Figure 21 Wiring Diagram, Models 1600, 2000 and 2400,

Codes B and E ................................................29

Figure 22 Wiring Diagram, Model 1200, Pump-Mounted,

Standard and Codes A, C, E, F and G ............30

Figure 23 Wiring Diagram, Models 1600, 2000 and 2400,

Pump-Mounted,

Standard and Codes A, C, E, F and G ............31

Figure 24 Wiring Diagram, Model 1200, Pump-Mounted,

Codes B and E ................................................32

Figure 25 Wiring Diagram, Models 1600, 2000 and 2400,

Pump-Mounted, Codes B and E......................33

Figure 26 Wiring Schematic, Model 1200,

Standard and Codes A, C, E, F and G ............34

Figure 27 Wiring Schematic, Models 1600, 2000 and 2400,

Standard and Codes A, C,E, F and G .............34

Figure 28 Wiring Schematic, Model 1200,

Codes B and E ................................................35

Figure 29 Wiring Schematic, Models 1600, 2000 and 2400,

Codes B and E ................................................35

Figure 30 Wiring Schematic, Model 1200, Pump-Mounted,

Standard and Codes A, C, E, F and G ............36

Figure 31 Wiring Schematic, Models 1600, 2000 and 2400,

Pump-Mounted,

Standard and Codes A, C, E, F and G ............36

Figure 32 Wiring Schematic, Model 1200, Pump-Mounted,

Codes B and E ................................................37

Figure 33 Wiring Schematic, Models 1600, 2000 and 2400,

Pump-Mounted, Codes B and E......................37

Figure 34 Gas/Air Test Panel ...........................................39

Figure 35 Test Panel Valves ............................................39

Figure 36 Gas Trains .......................................................43

Figure 37 Gas Train .........................................................44

Figure 38 Control Panel...................................................44

Figure 39 Combustion Components ................................50

Figure 40 Gas Train/Combustion Air Components ..........51

Figure 41 Gas Train Components ...................................52

Figure 42 Electrical Components ....................................53

Figure 43 Heat Exchanger / Water Path ..........................54

Figure 44 Jacket Components.........................................55

Rheos Boiler and Water Heater

Page 57

Page 58

LAARS Heating Systems

Rheos Boiler and Water Heater

Page 59

®

800.900.9276 • Fax 800.559.1583 (Customer Service, Service Advisors)

20 Industrial Way, Rochester, NH 03867 • 603.335.6300 • Fax 603.335.3355 (Applications Engineering)

1869 Sismet Road, Mississauga, Ontario, Canada L4W 1W8 • 905.238.0100 • Fax 905.366.0130

www.Laars.com

Litho in U.S.A. © Laars Heating Systems 1010 Document 1170F

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