Oil Steam Application Guide

Oil Steam Application Guide
®
STEAM / OIL
APPLICATION GUIDE
CAST-IRON MODULAR BOILERS
Guidelines for the design, purchase and installation of Slant/Fin oil-fired steam modular boiler systems.
CONTENTS
Introduction .............................................................................1
Ratings and dimensions .........................................................2
Boiler room air supply.............................................................3
Venting gas fired system .....................................................4,5
Fuel oil piping ......................................................................6,7
Typical steam system layout ...................................................9
Steam piping design ...............................................................9
Installation and piping ......................................................10,11
Boiler feed pump sizing ...................................................12,13
Wiring at module .............................................................14-17
Request for Caravan rating plate.....................................19-20
INTRODUCTION OF FRESH WATER
CODES AND STANDARDS
Oil-fired Caravan installations must comply to local codes or, in the
absence of local codes, to the ANSI/NFPA 31, Installation of Oil
Burning Equipment, latest edition.
In addition, where required by the authority having jurisdiction, the
installation must conform to American Society of Mechanical
Engineers Safety Codes for controls and safety devices for
automatically fired boilers, No. CSD-1. The installation must also
conform to the additional requirements of Slant/Fin Instruction Book
publication no. TR-40 latest edition.
All electrical wiring is to be done in accordance with the National
Electrical Code ANSI/NFPA No. 70-latest edition and all local
electrical codes. The unit must be electrically grounded if an external
power source is used.
In Canada, the installation must be in accordance with standards
CGA B149.1 and B149.2, installation codes for oil burning
appliances and equipment and/or local codes. All electrical
connections are to be made in accordance with Standard C.S.A.
C22.1 Canadian Electrical Code Part 1 and/or local codes.
Introduction of excessive amounts of fresh water into a system can
cause scaling and leave deposits in the boiler and the surrounding
pipes. This will lead to inefficient boiler operation and breakdown.
Fresh water will enter the system as a result of hidden leaks such
as may occur in underground piping. Relief valves should be piped
to a location that shows visible signs of relief.
Process applications that use fresh water, require the use of heat
exchangers. Any process application that results in introduction of
fresh water into a boiler can cause scaling with deposits forming in
the boiler and surrounding piping. This will damage the boiler.
Introduction of fresh water from leaks will cause similar damage.
Use of fresh water will void warranty.
In some areas it may be necessary to use a feed water treatment to
control the corrosive makeup of the feed water. Check with the local
authority, to determine if the feed water will need a conditioning
treatment before being supplied to the boiler.
INTRODUCTION
There are many varieties of steam heating systems. Because
of the wide range of field conditions, the design of these systems is beyond the scope of this manual. However, when
designing a steam Caravan boiler plant, certain guidelines
should be followed that are common to all modular steam
heating application.
This entire manual should be read prior to installing the
Slant/Fin Caravan steam system.
Safety – each module contains a LW.CO, ASME 15 lb Relief
valve and pressure gauge.
Publication No. CG-10-SO
Printed in the U.S.A. 415
Ratings
Oil Caravan ratings and dimensions/steam models — LDZO Series
Ratings for No. 2 Oil
AHRI
Model No.
Burner
No. of
Heating Capacity Input
Modules (GPH)* (MBH)
Net
Gross
Output Thermal Output
MBH Efficiency MBH†
Net
Sq.Ft
Steam‡
Horsepower
Boiler
Water
Content
(gal)
Weight
with
Water
Recommended
Header
Size
LDZO-600-2-5
LDZO-750-2-6
2
2
4.3
5.2
602
728
497
622
82.5
85.5
373
467
1554
1946
14.8
18.6
21.4
25.2
1426
1630
3"
3"
LDZO-850-2-7
LDZO-900-3-5
2
3
6.0
6.4
840
896
699
740
83.2
82.5
526
555
2192
2311
20.9
22.1
29.0
32.1
1838
2139
4"
4"
LDZO-1100-3-6
LDZO-1300-3-7
3
3
7.8
9.0
1092
1260
934
1048
85.5
83.2
700
789
2918
3287
27.9
30.6
37.8
43.5
2445
2756
5"
5"
LDZO-1700-4-7
LDZO-2100-5-7
4
5
12.0
15.0
1680
2100
1398
1747
83.2
83.2
1051
1314
4379
5474
41.8
52.2
58.0
72.5
3675
4594
6"
6"
* Light oil, 140,000 Btu. per gallon.
† Net ratings are based on piping and pick-up allowance of 1.33.
Slant/Fin should be consulted before selecting a boiler for installation having unusual piping and/or pick-up requirements.
For higher elevations, input may need to be reduced
‡ Based on 240 Btuh per square foot E.D.R. at 215˚F average
steam temperature.
Modules in excess of 5 are piped in parallel in two or more
banks.
Dimensions
* CHECK LOCAL CODES TO VERIFY COMPLIANCE
Dimensions*
Model No.
A
B
C
D
L
LDZO-600-2-5
215⁄8
87⁄32
8
343⁄8
4'4"
Design Data
LDZO-750-2-6
25
29
9 ⁄32
8
37 ⁄4
4'4"
LDZO-850-2-7
283⁄8
1119⁄32
9
411⁄8
4'4"
LDZO-900-3-5
215⁄8
87⁄32
8
343⁄8
6'7"
Max. ASME Working Pressure: 15 psi steam
Power Requirements: 120 V/60 HZ,
6.0 amps per module
LDZO-1100-3-6
25
929⁄32
8
373⁄4
6'7"
LDZO-1300-3-7
28 ⁄8
11 ⁄32
9
41 ⁄8
6'7"
LDZO-1700-4-7
283⁄8
1119⁄32
9
411⁄8
8'10"
LDZO-2100-5-7
283⁄8
1119⁄32
9
411⁄8
11'1"
3
* Inches, except “L” which is feet/inches.
2
19
3
1
BOILER PLANT SIZING
BOILER ROOM AIR SUPPLY
Older buildings may have a heat loss significantly less than that
of the original building. To size a replacement steam boiler
plant, consider the following: Replacement steam boiler plants
must be sized to match the connected radiation load. Undersizing will prevent steam from reaching distant radiation quickly
To ensure safe, efficient operation, the modular boiler system must
be supplied with sufficient air to support complete combustion,
replacing air entering draft dampers or draft hoods and ventilating
the boiler room or areas. For additional information, not listed
below, see ANSI,Z223.1, section 5.3.3.
BOILER ROOM DESIGN
Caravan modular boiler systems allow better utilization of floor
space and permit future expansion with minimum cost. Caravan
modules are hand truckable, fit through doorways and often may
be installed around an existing inoperative boiler. They can be
grouped in heating module batteries of single, multiple or angular
rows. Oil-fired boiler systems consisting of 9 or more modules
should be piped in parallel in two or more batteries. Illustrated
below are typical boiler room layouts and dimensional data on the
size requirements of oil-fired hot water boilers.
INSTALLATION IN ENCLOSED BOILER ROOM REQUIRES
TWO UNOBSTRUCTED OPENINGS FOR PASSAGE OF
AIR INTO THE BOILER ROOM:
1. Air drawn horizontally from outdoors DIRECTLY
through an outside wall; one louvered opening near
the floor (below burner air inlet) and one louvered
opening near the ceiling (above the highest draft
regulator), each opening with a minimum FREE air
passage area of 1 square inch per 4000 BTUH of total
system input.
2. Air drawn horizontally from outdoors through
HORIZONTAL DUCTS; one opening near the floor (below
burner inlet) and one opening near the ceiling (above the
highest draft regulator), each opening with a minimum
FREE air passage area of 1 square inch per 2000 BTUH
of total system input.
3. Air drawn VERTICALLY from outdoors; one opening
at the floor and one opening at the ceiling, each opening
with a minimum FREE air passage area of 1 square inch
per 4000 BTUH of total system input.
4. Air drawn from inside the building; one opening near
the floor (below burner inlet) and one opening near the
ceiling (above the highest draft regulator), each opening
with a minimum FREE air passage area of 1 square inch
per 1000 BTUH of total system input.
Figure 11. Correct location of combustion-air supply ducts
IF BOILERS ARE INSTALLED ADJACENT TO OTHER FUEL
BURNING EQUIPMENT, THE AREA OF FREE OPENINGS
MUST BE APPROPRIATELY INCREASED TO ACCOMMODATE
THE ADDITIONAL LOAD.
UNLESS PROPERLY CONTROLLED, AVOID THE USE OF
FORCED VENTILATION, SINCE IT CAN CREATE AN
UNDESIRABLE PRESSURE DIFFERENTIAL BETWEEN
BOILER ROOM AND AIR SOURCE.
3
VENTING A OIL-FIRED SYSTEM
A boiler venting system provides draft and an escape path for the
products of combustion. In a venting system for an oil-fired
Caravan, there are three major components: a riser with draft regulator for each module, a breeching manifold, and a chimney.
Sometimes the venting system for a boiler plant has to be
designed to compensate for inadequate chimney conditions. A
mechanical draft inducer, properly sized and installed, can usually
increase chimney capacity sufficiently to provide proper venting.
Where a draft inducer is called for, consult local codes and the
recommendations of the mechanical draft inducer manufacturer.
Normally, a draft proving device is necessary to permit operation
of the boilers only when adequate draft exists.
It is important to note that when considering a mechanical draft
inducer, the boiler room air supply requirements must be
increased. Consult the draft inducer manufacturer for this
information.
Draft Regulator
The draft regulator compensates for excessive draft that can be
caused by varying weather conditions. The regulator should be of
the barometric-draft type. Once adjusted for a particular venting
system, this type regulator automatically compensates for
excessive draft to assure optimum operating efficiency.
To avoid creating turbulent air patterns in the breeching, it is
suggested that individual boiler vent pipes be connected to the
breeching as indicated in Figure 13.
The breeching manifold should extend into, but not beyond, the
chimney liner. Round breeching is preferable to rectangular
breeching.
Chimney
Caravan oil-fired modular boilers operate efficiently with masonry
or prefabricated chimneys. This latter type of chimney construction
is generally the least expensive.
Minimum chimney sizes and heights are given in Table 4. In
addition, the chimney should be high enough to minimize the
effects of turbulent winds and high pressure areas common near
roof-top obstructions. The National Board of Fire Underwriters
recommends that the chimney should extend 3 feet above the roof
and be 2 feet higher than any obstruction within 10 feet (figure
13). The use of a vent cap where permitted by code gives additional protection against adverse wind conditions and precipitation.
Table 4. Chimney requirements
Chimney Liner Inside Dim. †
Model No. *
Breeching
Breeching is a term used to describe a manifold(s) that connects
individual boiler modules to a chimney. Breeching is usually
constructed of sheet metal having a smooth interior surface with
all joints made tight against leakage. The layout of a particular
boiler room may require that the modules be arranged in
"batteries" with rows either parallel or at right angles. Minimum
breeching sizes are given in Table 3.
Table 3. Breeching dimensions for oil-fired systems —
LDZO Series
Model No. *
No. of
Modules
Breeching
Diameter
LDZO-600-2-5
LDZO-750-2-6
LDZO-850-2-7
LDZO-900-3-5
LDZO-1100-3-6
LDZO-1300-3-7
LDZO-1700-4-7
LDZO-2100-5-7
2
2
2
3
3
3
4
5
11"
12"
13"
13"
14"
15"
16"
18"
Minimum
Area
Breeching
(sq.in.)
Length
84
101
115
123
148
170
189
233
4'8"
4'8"
4'8"
7'1"
7'1"
7'1"
9'6"
11'11"
* Dual fuel prefix = LWDF.
Notes:
1. For breeching and chimney sizing over 8 modules, consult factory.
2. Breeching length should be as short as possible. Measurement from the
base of the vertical vent to the nearest connected appliance should be
limited to 10' or 50% of the total vent height, whichever is greater.
4
LDZO-600-2-5
LDZO-750-2-6
LDZO-850-2-7
LDZO-900-3-5
LDZO-1100-3-6
LDZO-1300-3-7
LDZO-1700-4-7
LDZO-2100-5-7
No. of
Dia.
Modules Inches
2
2
2
3
3
3
4
5
11"
12"
13"
13"
14"
15"
16"
18"
Rectangular
L xW
Inches
Minimum
Height
Feet
93⁄4" X 93⁄4"
91⁄2" X 131⁄2"
131⁄4" X 131⁄4"
131⁄4" X 131⁄4"
131⁄4" X 131⁄4"
13" X 17"
13" X 17"
163⁄4" X 163⁄4"
20'
20'
20'
20'
20'
20'
25'
25'
Sizing Horizontal Breeching Connectors and Chimneys for
Oil-Fired Systems
* Dual fuel prefix = LWDF.
† Dimensions shown are from ASHRAE Guide Equipment Handbook. Also
select inside liner dimensions to give area as great or greater than shown in
this table. Chimney height is measured from the center line of the breeching
to the top of the chimney. Chimney dimensions are approximate, with no
manifold elbows or tees; and good vent construction practices. Field
conditions vary. It is doubtful that the chimney dimensions shown here will
be suitable for all applications. Consult the 2000 ASHRAE Equipment
Handbook and Chimney Manufacturers Sizing Handbook.
Horizontal breeching connectors shall be constant sized. The
chimney and the horizontal breeching connector are sized using
table 3.
When there are multiple banks of boilers, the horizontal breeching
connector for each bank is sized using table 3. To size the common horizontal breeching connector, add up the total input and
refer to table 3 to size.
The minimum chimney will be equal to the size of the largest horizonatl breeching section connected to it.
Figure 13. Suggested venting system constructions
5
FUEL OIL PIPING
FUEL OIL STORAGE FACILITIES
Local codes usually govern the installation of fuel oil storage
facilities. However, for areas where no rules have been established,
the following information can provide assistance to the system
designer.
Storage tank sizing
When calculating minimum fuel oil storage capacity, several
variables must be considered. These include: maximum fuel
consumption rate, storage space limitations, availability, distance
from source of supply, and method of delivery (truck or railroad tank
car). Large storage tanks, of course, cost more than smaller ones
but the cost is not proportional (e.g., a 10,000 gal. tank does not
cost twice as much as a 5,000 gal. tank). And larger tank capacity
allows oil purchases usually at lower per gallon rates.
g) Fiberglass and/or double-walled tanks may be required. Check your
local codes. Underground metal tanks should be painted with heavy
asphaltum, rust-resistant paint or be of double walled construction
(check local codes). DO NOT install tank in bed of cinders (cinders
contain sulphur, which becomes corrosive when wet).
NOTE: Before installing underground tanks, check local surface
water conditions. Where potential problems exist, concrete
anchors should be provided. Follow per local and national codes.
Generally, the storage tank should hold enough oil to sustain
continuous operation for 10 days (plus an additional 10% margin to
allow for suction stub clearance).
To determine the minimum storage requirement, proceed as
follows:
a) Refer to Table 1 to find the maximum hourly oil consumption
(GPH) of the system being installed.
b) Multiply the maximum hourly consumption by the probable
maximum daily hours of operation to achieve maximum daily
consumption.
c) Multiply the maximum daily consumption by 10 (days) and add
10% to obtain the MINIMUM storage capacity.
Requirements for fuel oil storage tanks.
Data in this section is based on the use of steel storage tanks.
Where no local codes apply, take the following data into
consideration.
a) Inside tanks are usually located in the lowest part of the building.
When supply and return lines are piped through the top of the
tank, spillage is minimized in the event of leaks.
b) Unenclosed tanks should be at least 7 feet from any open
flames or fires.
c) Most fire codes prohibit unenclosed inside tanks exceeding 275
gallons each. Where multiple tanks are installed, the total storage
capacity should not exceed 550 gallons unless vaulted.
d) If inside tanks are properly enclosed, the maximum storage
capacity can be increased to 5,000 gallons in non-fire-resistant
buildings, and to 15,000 gallons in fire-resistant structures.
NOTE: An enclosure shall consist of walls constructed of 6"
reinforced concrete or 8-inch thick masonry with the space
between tank and walls filled with sand. If floor above has a
load-bearing capacity of 150 lbs./sq. inch or greater and is
constructed of fire-resistant material, 1 foot of sand fill over the
tank is sufficient. If not, a 5-inch concrete slab, or equivalent,
must be employed. An alternative method is to pour a 6-inch
thick concrete enclosure directly over the tank (no air spaces).
e) Underground tanks (Figure 14) are to be buried at least 2 feet
below grade.
f) Tanks buried beneath buildings ALWAYS require 4-inch
reinforced concrete slab covers that extend 1 foot beyond tank in
all directions.
6
Figure 14. Typical example of properly installed
underground fuel tank
FUEL OIL DELIVERY SYSTEMS
FOR SINGLE FUEL BURNERS
General
Three methods for delivering oil to the individual burners are
described herein. These methods are chosen to provide tempered,
filtered and air-free oil to the individual burners. Consistent oil
quality will optimize burner operation over longer periods.
There are variations to the methods described herein which, if
applied properly, will result in acceptable operation. These methods
are for reference only. Local codes vary. It is important to check all
codes for compliance.
Information herein has been compiled using data from industry
sources, including companies such as Mitco, Webster, Suntec and
Tuthill. For additional information on these products, contact the
representative in your area.
MFG data and safety codes vary with regard to maximum fuel unit
inlet pressure. Pay particular attention to the gravity oil head. Be
sure to add oil pressure reducing valves in the event that codes or
MFG data will be exceeded. 5 psi is equivalent to approximately 12
feet in height. (See "H" dimension.)
Storage tank above burners (Figure 15)
A simple one pipe connection from the supply tank to each burner
helps to eliminate air in the oil line and tempers the oil in the pipe
as it travels slowly to the burners.
This method maintains consistent fuel oil quality to the individual
burners and therefore decreases the frequency of maintenance and
service. When a component breakdown occurs in a burner or in the
supply system, the trouble is easily found and service is restored
quickly.
Storage tank below burners and gravity tank above
burners (Figure 16)
Oil is automatically and constantly maintained in the supply tank at
a level sufficient to meet all burner needs. As oil is used, the
pressure drop is sensed by a pre-set automatic pressure switch,
which signals the booster pump to restore proper level. There is no
practical limit on the height or distance that the motorized pump can
deliver oil to the supply tank.
The great advantage of the booster pump along with a gravity tank
is that it accomplishes its purpose in the most simple and direct
manner. This results in the most economical installation, with the
shortest possible runs of pipe and wire. It also enables the installer
to adapt with ease to almost any building configuration. A simple
one pipe connection to each burner helps eliminate air in oil line
with constant flow of fuel and tempers the oil.
Simplicity of operation of the individual burner decreases the
chances that service will be needed. When a component breakdown
occurs in a burner or in the supply system, the trouble is easily
found and service is restored quickly.
Figure 15. Storage tank above burners
Figure 16. Storage tank below burners
7
(1) Defined as the connection distance between storage tank and inlet of booster pump.
(2) Height of booster pump inlet above bottom of storage tank. If higher lift is
needed, contact booster pump manufacturer with exact requirements.
(3) Total suction length equals vertical lift plus horizontal distance between suction
line connection at storage tank and inlet of booster pump.
(4) 5/8" tubing allows maximum horizontal distance between supply tank outlet
and booster pump inlet to be safely increased by 250%.
(5) Maximum fuel oil consumption rate with Suntec BH-1030M pump.
(6) Maximum fuel oil consumption rate with Suntec BH-1050M pump.
(7) Supply line is defined as the connection between the outlet of the booster
pump and the inlet of the supply tank.
(8) Total supply line length equals vertical lift plus horizontal distance between
booster pump outlet and supply tank inlet.
(9) Boiler feed line is defined as the connection between the gravity feed tank and
the furthest burner.
Figure 17. Wiring diagram for gravity feed booster- pump operation
Components usually required are a motorized booster pump of sufficient capacity,
gravity tank and mounting hardware, automatic oil level pressure switch, vacuum
breaker and necessary check valves and fittings. Additional information can be
obtained from Mitco Manufacturing, Hicksville, New York.
Duplex booster pumps are desirable to provide standby capability, in the event of
booster pump failure.
a) Using Table 1, find maximum total firing rate of the boiler system being installed.
b) Find the vertical and horizontal dimensions of the booster pump's suction line.
c) Make sure the suction line lift and length are with capabilities of typical booster
pumps. Refer to Table 5. (This data is based on Suntec models BH-1030M at
30 GPH, and BH-1050M at 50 GPH or equivalent.)
NOTE: If lift is excessive (max. 6" Hg one stage, 15" Hg two stage), contact pump
manufacturer with exact requirements. If total length is too long, increase suction
line diameter.
d) Using Table 6, find correct supply line size.
Table 5. Maximum booster pump suction line length (1)
Maximum Total Suction Line Lengths (3)
1/2" O.D. copper tubing (4)
8
Firing Rates
up to 30 GPH (5)
0 - 7'
8 - 10'
11 - 13'
14 - 15'
100'
80'
63'
52'
Firing Rate
Up to 30 GPH (5)
Up to 50 GPH (6)
Supply Line Size
Maximum Total Supply Line Length (8)
300'
175'
1
⁄2" O.D. tube
800'
350'
1
⁄2" pipe
2500'
1500'
3
⁄4" pipe
Table 7. Boiler feed line sizes (9)
Sizing booster pump
To determine the correct size of a booster pump:
Vertical
Lift (2)
Table 6. Supply line sizes for high-volume fuel oil
delivery systems (7)
Firing Rates
up to 50 GPH (6)
63'
53'
41'
34'
Total Length
Maximum
25'
75'
200'
Firing Rates
up to 30 GPH (5)
1
⁄2" O.D. tube
1
⁄2" pipe
3
⁄4" pipe
Firing Rates
up to 50 GPH (6)
1
⁄2" O.D. tube
1
⁄2" pipe
3
⁄4" pipe
Table 8. Line Length for Two-Stage Fuel Unit
Two Pipe
Lift Ht.
1'
2'
3'
4'
5'
6'
7'
8'
9'
10'
11'
12'
13'
14'
15'
1/2" O.D. Tubing
A
B
118
113
107
102
96
91
86
80
75
69
64
58
53
47
42
99
95
90
86
81
76
72
67
61
58
54
49
44
40
35
5/8" O.D. Tubing
A
B
328
313
298
283
268
253
238
222
207
192
177
162
147
131
116
A = B82 Series Suntec Pump 63 GPH gear capacity.
B = B89 Series Suntec Pump 75 GPH gear capacity.
276
263
250
237
225
212
200
187
174
161
148
136
123
110
98
Figure 7. Typical Three Module Bank (LDZO-1300-3-7)
SHUT OFF
VALVE
BALANCING
VALVE
CHECK
VALVE
SEE PG. 14
FOR MORE
DETAIL PIPING
CONDENSATE
RETURN DRAIN VALVE
SYSTEM CONDENSATE
RETURN AND MAKE UP
FROM FEED PUMP
MODULE REAR
1-1/2” RETURN TRAP (TYPICAL)
EQUALIZER LINE
FEED PUMP
RECEIVER TANK
CONDENSATE
RETURN
FROM SYSTEM
MODULE FRONT
BOILER DRAIN VALVE
VENT
MAKE-UP WATER
CARAVAN STEAM HEATING SYSTEM CONDENSATE RETURN
Figure 7a.
9
STEAM SUPPLY AND RETURN PIPING
Modular steam boilers must be piped in a way that provides nearly equal steam pressure at all modules. Supply and return pipes
and fittings should be identical on each module. The pressure
drop in the supply header, between the connection to the building
and the supply tapping on each module must be kept to a minimum. When installed properly, this will result in minimal variance
in water levels between modules. Figure 8 shows the take off to
the system after the last module and before the equalizer/drain
line. Header size shown on this page (Table 8) is based on this
piping arrangement. Figure 9 shows the piping arrangement
between the module and header connections. In this area, try to
keep the number of elbows to a minimum (maximum 3). It is
important to note that a pressure difference of as little as one
ounce (1/16 PSI) between modules will result in a water level difference of almost 2 inches.
Table 8: Modular steam boiler plant header pipe sizing
No. of
Modules
Capacity Steam
EDR
Oil
2
2 or 3
3 or 4
4
1946
2311
3287
4379
Header Pipe Sizes
Supply
Return
Oil
3"
4"
5"
6"
1.5"
2.0"
2.0"
2.0"
Maximum 5 modules per bank.
Figure 8: Piping details
Figure 10: Steam supply header
at oil modules
Figure 9: Steam supply header piping
10
INSTALLATION AND PIPING RECOMMENDATIONS
When one or more steam boilers are replaced with a new Caravan
modular boiler system, there are certain conditions that must be
considered.
1. All modules must be set on a level surface, and individually
leveled.
2. Modules should be mounted on a 3" high level concrete base.
3. 2" minimum clearance between modules.
4. 2" rear supply tap on module must be piped into the 3" front
supply pipe as shown in Fig. 10 on page 10 to minimize
pressure drop, no more than three 90˚ elbows should be
installed between the module supply tapping and steam header
(See figure 9, page 10)
5. All banks of modules must have an equalizer/drain line from
the supply header to the return header. This equalizer/drain
should be located at the end of the header that the system
steam supply is taken from. The equalizer/drain should be the
same size as the supply header (see figure 8, page 10). The
supply & return header for each bank should be sized
according to Table 8, page 10.
6. To prevent accumulation of condensate, steam headers
should be pitched down in the direction of steam flow and
toward the equalizer/drain with no reduction in size. Module
connections must be on the side of the header (horizontal) or
at any angle between the side and top of header, never
between the side and bottom. To prevent condensate in the
header from re-entering the boiler supply pipe, side connections must enter a header that is at least one size larger than
the boiler supply connections. Top or 45˚ top-angle connections are preferred and can enter a header of the same size
or larger. See Figure 9. The supply header for each module
should be sized according to Figure 10, page 10.
7. The supply connection between the building steam main and
the module steam header should be located between the last
boiler on the header and the equalizer/drain. Connection
must be at least 2 header diameters from the last module
(see Figure 8, Page 10).
8. Piping should provide a means for both surface and bottom
blow-down and flushing sediment from the system for clean,
safe and efficient operation (see Figure Fig. 7 page 9).
9. The use of a pump control is recommended to regulate the
water level in a bank of boilers and prevent the bank from
operating with an unsafe low water condition. For protection
of banks with 2 to 5 modules, the control should be located
on the equalizer line. All applications require a low water
cut-off on each module and one cut off for each bank.
10. Supply and/or return shut-off valves on individual modules
are not recommended. However, if valves on individual
modules are unavoidable, additional safety controls are
required on each module. Full-port valves should be used to
minimize pressure drop and should be the same diameter as
the pipe.
11. Impurities and oxygen in fresh water cause scaling and leave
deposits in the boiler and surrounding pipes. This leads to
inefficient operation and other system problems. The older
the system, the greater the probable accumulation of scale.
Therefore, it is necessary to check the piping for blockage or
restriction and clean or replace the piping as required.
Applications such as process systems can result in excessive
introduction of fresh water into a steam boiler. This will damage the boilers and void any warranty. Caravan modular
boiler systems are not recommended for applications
involving the use or discharge of raw steam or condensate.
In all cases, boiler water should be tested periodically to
deter mine if conditioning treatment is needed. Consult a
local boiler water treatment expert.
11
Figure 11: Steam modules, isolated banks (Note: For detail piping refer to pages 8 & 9)
Figure 12: Steam modules, integrated banks (Note: For detail piping refer to pages 8 & 9)
12
12. Caravan modular boiler systems are often used as a replacement for old, large, inefficient boilers. Compared with older
boilers, modern steam boilers have a relatively small water
volume in the operating range. The result can be that a
normal volume of condensate return water could create high
water levels in the new modules. In most systems, the use of
a combination feed-pump and receiver will prevent flooding.
The recommended storage capacity for the receiver is shown
in Table 9. This table is based on condensate returned to the
receiver within twenty minutes of start-up. If the time required
for returning condensate is greater, a larger receiver would be
needed. Check with the fee pump manufacturer for the
correct size. The feed-pump/receiver is used to store condensate returned from the system, provide feed-water to the
boilers, as regulated by the pump control and add makeup
water to the system.
A balancing valve MUST be provided on the feed-pump discharge line. This valve is used to adjust water volume to
prevent feed-water from entering the boilers too quickly, which
can cause water levels to “bounce”. The pump discharge
pressure must be slightly higher than the steam operating
pressure. A rate of 1 GPM per module is more than sufficient
to feed a steam Caravan system (see Table 9). The feed
pump is activated by a pump control mounted on the
equalizer drain line, (see Figure 8, page 10). When the
boiler water level drops, the pump control energizes the feedwater pump, transferring feed-water from the receiver to the
bank of modules. On systems with more than one bank of
boilers that are isolated (valved), each bank must have a
dedicated feed-pump with a dedicated power supply, (see
Figure 11, page 12). This will prevent the operation of one
bank of boilers from interfering with another.
During operation, condensate from the heating system is
constantly being returned to the receiver. It is natural that
some steam / condensate will be lost through venting and
small, undetected leaks in the system. When the receiver
water level drops below a predetermined low level, a float
mechanism allows make-up (fresh) water to enter the receiver
and replace any water lost in the system. However, if this is
occurring frequently, the system should be checked for leaks.
The use of a water meter in the make-up line is
recommended.
Certain local codes may require a Hartford Loop. However,
the use of a Hartford Loop is otherwise not recommended
when using a feed-pump. Consult your local authorities.
WARNING: The description in this manual is for a boiler
feed-pump only. Do not use a “condensate pump” in place of
a feed-pump on a Caravan system. Unlike a feed-pump, a
condensate pump will pump water into the boilers regardless
of the boiler water level. Some systems may require the use
of condensate return pumps in distant parts of the system.
These condensate pumps must discharge into the boiler
feed-pump/receiver, not into the boilers.
13. All equipment such as steam traps and air vents in the steam
heating system should be checked for proper operation and
replaced or repaired as needed. All piping should be
checked for proper pitch.
14. It is good practice to re-pack and/or tighten the packing nuts
on all valves in the system.
Table 9: Boiler feed pump and receiver sizing
Gas
No. of
Modules
Min.
GPM
Oil
Net
Storage
Min.
GPM
Net
Storage
1
.65
13
.75
15
2
1.30
26
1.50
30
3
1.95
39
2.25
45
4
2.60
52
3.00
60
5
3.25
65
3.75
75
6*
3.90
78
4.50
90
7*
4.55
91
5.25
105
8*
5.20
104
6.00
120
9*
5.85
117
6.75
135
10*
6.50
130
7.50
150
11*
7.15
143
8.25
165
12*
7.80
156
9.00
180
13*
8.45
169
9.75
195
14*
9.10
182
10.50
210
15*
9.75
195
11.25
225
* Maximum 5 modules per bank.
On systems with more than one bank of boilers, each bank must have a
dedicated feed-pump with its own power supply. This will prevent the
operation of the one bank of boilers from interfering with another.
Definitions of terms
• Make-up water: Fresh water introduced into the system to
compensate for evaporation, leaks, blow-down and other use of
steam or condensate.
• Condensate water: Water that has been condensed from steam
in the system.
• Feed-water: Any mixture water, both condensate and make-up, that
enters the boilers to maintain water level.
• Header: The pitched horizontal pipe connecting the modules where
steam or condensate flows to or from a bank of modules.
13
OVERFLOW
CONDENSATE
RETURN
L
VE
R
LE
OI
LE
MAKE UP
WATER
TANK WATER
LEVEL AT/
OR BELOW
BOILER LEVEL
B
NORMAL TANK
WATER LEVEL
SHUT-OFF
VALVE
STRAINER
PUMP
SHUT-OFF
VALVE
STRAINER
TO ADDITIONAL PUMPS
(AS NEEDED)
PUMP
CHECK
VALVE
TO ISOLATED
BANK
BALANCING
VALVE
SHUT-OFF
VALVE
NOTES:
1. Maximum of five modules per bank.
BOILER
WATER
LEVEL
RETURN
MANIFOLD
2. Each isolated (valved) bank must have
a manual reset low water cut-off,
manual reset high pressure cut-off,
pump controller and dedicated feed pump.
GSTM-13
Figure 13: Installation with receiver tank water level at or below modules normal water levels
OVERFLOW
CONDENSATE
RETURN
EACH BANKS BOILER FEED LINE
MUST BE RAISED TO A LEVEL
ABOVE FEED TANK OVERFLOW
MAKE UP
WATER
TANK WATER
LEVEL ABOVE
BOILER LEVEL
NORMAL TANK
WATER LEVEL
SHUT-OFF
VALVE
STRAINER
L
PUMP
VE
R
LE
I
BO
SHUT-OFF
VALVE
STRAINER
LE
TO ADDITIONAL PUMPS
(AS NEEDED)
PUMP
TO ISOLATED
BANK
CHECK
VALVE
BALANCING
VALVE
SHUT-OFF
VALVE
BOILER
WATER
LEVEL
RETURN
MANIFOLD
NOTES:
1. Maximum of five modules per bank.
2. Each isolated (valved) bank must have
a manual reset low water cut-off,
manual reset high pressure cut-off,
pump controller and dedicated feed pump.
GSTM-13A
Figure 13A: Installation with receiver tank water level above modules normal water levels
14
MODULAR STEAM WITH SPACE TEMPERATURE CONTROL WIRING DIAGRAM
Sequence of operation
When the building thermostat calls for heat, contacts (RC)
of the R8285B control closes. This energizes the coils of
R1 and R2 relays. With these contacts closed, all the
modules are energized to fire. This will bring the system
pressure up quickly. The P404A pressure controls on each
module (not shown in diagram, see figure. 16) are set to
the pressure required to heat the building. This will stage
the numbers of modules firing to meet the demands of the
building load. The required modules will continue to fire
until the thermostat is satisfied.
There are several manufacturers that provide more sophisticated controls for modular steam systems.
Figure 14: Space temperature control wiring diagram
15
Figure 15: Space temperature control ladder diagram
16
Figure 16: Wiring at module
17
Notes:
18
CARAVAN SYSTEM RATING PLATE
System rating plate format for Caravan modular boiler system.
System rating plates are available upon request using the form on the back cover.
19
REQUEST FOR CARAVAN SYSTEM RATING PLATE
Each individual Caravan module is shipped with a rating
plate bearing the model, serial number, capacities and
certifications for that module. A modular boiler system is a
single boiler. To meet local requirements, a system rating
plate will be issued by Slant/Fin upon request. Just
provide the information indicated on this page.
Slant/Fin Tech
Service
Requested by:
Phone:
Mail to:
Phone:
FAX THIS REQUEST TO:
516-484-6958
PHONE:
516-484-2600
Required
Required
NOTE:
INDICATE ACCURATELY
Some model numbers are similar, such as GGT-600 and GGT-600E etc.
PLEASE USE CARE TO MAKE SURE THE PROPER SYSTEM MODEL IS INDICATED
COMPLETE WITH LETTER SUFFIX.
BE ACCURATE!
INCLUDE ALL LETTERS AND ZEROS, ENTER ALL INFORMATION ASKED FOR!
USE A SEPARATE FORM FOR EACH SYSTEM
Type of System:
Gas
Natural Gas
Oil
Propane
Water
Steam
INDICATE SYSTEM MODEL
NUMBER BELOW:
INDICATE SERIAL NUMBERS OF INDIVIDUAL MODULES (Please write legibly)
DO NOT WRITE BELOW THIS LINE • FOR SLANT/FIN USE ONLY
System serial number assigned
Done by
SLANT/FIN CORPORATION, Greenvale, N.Y. 11548 • Phone: (516) 484-2600
FAX: (516) 484-5921 • Canada: Slant/Fin LTD/LTEE, Mississauga, Ontario
www.slantfin.com
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