Green Mountain GMGS Instruction manual

P/N# 240009192, Rev. C [10/2012]
GMGS
Cast Iron
Steam
Gas Fired
Boilers
INSTALLATION, OPERATION & MAINTENANCE MANUAL
Models
GMGS075 GMGS225
GMGS112 GMGS262
GMGS150 GMGS299
GMGS187
Manufacturedby:
ECRInternational,Inc.
2201 Dwyer Avenue, Utica NY 13504-4729
web site: www.ecrinternational.com

2
Safety Symbols .............................................................................................................. 3
Boiler Ratings And Capacities ........................................................................................... 4
Before You Start ............................................................................................................. 5
Locating The Boiler ......................................................................................................... 5
Fresh Air For Combustion................................................................................................. 6
Installation - System Piping ............................................................................................. 7
Chimney And Vent Pipe Connection ................................................................................. 12
Vent Damper Operation................................................................................................. 13
Gas Supply Piping......................................................................................................... 14
Electrical Wiring ........................................................................................................... 16
Controls And Accessories ............................................................................................... 22
Operating Instructions................................................................................................... 23
Intermittent Ignition Boiler - VR8204A/VR8304M Gas Valve Operating Instructions................ 24
Continuous Pilot Boiler - VR8200A/VR8300A Gas Valve Operating Instructions ...................... 25
Operating Instructions................................................................................................... 24
Checking and Adjusting ................................................................................................. 26
Cleaning Your Boiler...................................................................................................... 28
Maintaining Your Boiler.................................................................................................. 29
Service Hints ............................................................................................................... 31
Repair Parts................................................................................................................. 32
KEEP THIS MANUAL NEAR BOILER
RETAIN FOR FUTURE REFERENCE
GMGS
GAS FIRED BOILERS
STEAM BOILERS
TABLE OF CONTENTS

3
SAFETY SYMBOLS
Following defined symbols are used throughout this
manual to notify reader of potential hazards of varying risk
levels.
READ AND UNDERSTAND ALL INSTRUCTIONS BEFORE
INSTALLING.
NOTICE
Used to address practices not related to personal
injury.
CAUTION
Indicates a hazardous situation which, if not avoided,
could result in minor or moderate injury.
!
!
WARNING
Indicates a hazardous situation which, if not avoided,
could result in death or serious injury.
!
DANGER
Indicates a hazardous situation which, if not avoided,
WILL result in death or serious injury
!
WARNING
Fire, explosion, asphyxiation and electrical shock
hazard. Improper installation could result in death or
serious injury. Read this manual and understand all
requirements before beginning installation.
!
WARNING
Keep boiler area clear and free from combustible
materials, gasoline and other flammable vapors and
liquids.
Do not obstruct air openings to boiler room.
Modification, substitution or elimination of factory
equipped, supplied or specified components may
result in, personal injury or loss of life.
Boiler installation shall be completed by qualified agency.

4
BOILER RATINGS AND CAPACITIES
Table 1 - Ratings and Capacities
BOILER MODEL NUMBER (1) No. of
Sections
†Natural Gas †Propane Gas Dimensions
(Inches)
Input
*MBH
Heating
Capacity
*MBH
Net
I=B-R
Rating
*MBH
Net
I=B=R
Rating Sq.
Ft.
Input
*MBH
Heating
Capacity
*MBH
Net
I=B=R
Rating
*MBH
Net
I=B=R
Rating
Sq. Ft.
Radiation
Flue
Diameter "A" Width
GMGS075 3 75 62 47 196 70 58 44 183 5 11¼
GMGS112 4 112 91 68 283 105 85 64 267 6 14½
GMGS150 5150 122 92 383 140 114 86 358 6 17¾
GMGS187 6 187 153 115 479 175 143 107 446 7 21
GMGS225 7 225 183 137 571 210 171 128 533 7 24¼
GMGS262 8 262 214 161 671 245 200 150 625 7 27½
GMGS299 9 299 245 184 767 280 229 172 717 7 30¾
* MBH = 1,000 Btuh. Btuh = British Thermal Unit Per Hour.
** Add 5½" to height for Vent Damper
† For altitudes above 2,000 ft. reduce input rate 4% for each 1,000 ft. above sea level.
Heating Capacity is based on DOE (Department of Energy) test procedure.
(1) Add suffix E for electronic ignition and V for standing pilot.
Net I=B=R steam Ratings shown are based on piping and
pickup allowance of 1.333.
Base selection of boiler size on "Net I=B=R Rating"
being equal to or greater than installed radiation in
square feet. Consult manufacturer before selecting
boiler for installations having unusual piping and pickup
requirements,such as intermittent system operation,
exhaust piping systems, etc.
Specifications and dimensions are subject to change
without notice.
Figure 1 - Dimensions

5
BEFORE YOU START
• Verify you have right size boiler before starting
installation. See rating and capacity table on previous
page.
• Verify boiler is for type of gas you are using. Check rating
plate on right side of boiler.
• Verify boiler is supplied with correct type of gas, fresh air
for combustion, and suitable electrical supply.
• Verify boiler is connected to suitable venting system and
adequate piping system.
• Thermostat is needed for control of heating system and
properly located.
• Check with local authorities and obtain professional help
where needed. Take time to complete all steps for SAFE
and PROPER operation of heating system.
• If this boiler is installed in building under construction,
special care must be taken to insure clean combustion air
supply during construction process. Airborne particulates
such as from drywall dust and from fiberglass insulation
can clog burner ports and cause incomplete combustion
and sooting.
• Boilers are designed for use in closed heating systems
where all steam is returned to boiler as condensate and
amount of make-up water required is minimal.
• Boilers are not designed for or intended for use in open
systems of process applications using 100% make-up
water. Damage to boiler resulting from such use shall
not be covered under warranty.
• Where required by authority having jurisdiction,
installation must conform to the Standard for Controls
and Safety Devices for Automatically fired Boilers, ANSI/
ASME CSD-1.
• Installation must conform to requirements of the authority
having jurisdiction or, in absence of such requirements, to
National Fuel Gas Code, ANSI Z223.1/NFPA 54.
• Following steps are all necessary for proper installation
and safe operation of your boiler.
A. Locating boiler
B. Fresh air for combustion
C. Installation - system piping
D. Chimney & vent pipe connection
E. Gas supply piping
F. Electrical wiring
G. Checking & adjusting
LOCATING THE BOILER
1. Select level location as centralized with piping system,
and as near chimney as possible.
2. Place crated boiler at selected location, remove crate
by pulling crate sides from top and bottom boards.
WARNING
Fire hazard. For installation on non-combustible
floors only (for installation on combustible flooring
special base must be used). Do not install boiler on
carpeting.
!
3. FOR INSTALLATION ON NON-COMBUSTIBLE
FLOORS ONLY - For installation on combustible
flooring special base must be used. (See Replacement
Parts Section.) Boiler can not be installed on
carpeting.
4. Boiler is to be level. Metal shims may be used under
base legs for final leveling.
5. Install equipment in location in which facilities
for ventilation permit satisfactory combustion of
gas, proper venting, and maintenance of ambient
temperature at safe limits under normal conditions of
use.
6. Equipment shall be located so as not to interfere with
proper circulation of air. When normal infiltration
does not provide necessary air, outside air shall be
introduced (See Page 6 - “Fresh Air for Combustion”).
Table - 2 Minimum Clearance
Dimensions
Top 6"
Rear 6"
Control Side 7"
Opposite Side 6"
Front Alcove
Flue/Vent Connector 6"
Near Boiler Piping 1"
Set boiler on concrete or other non-
combustible material base or floor.
7. Advise owner to keep air passages free of obstructions.
Ventilating and combustion air must enter boiler room
without restrictions.
8. Install boiler such that automatic gas ignition system
components are protected from water (dripping,
spraying, rain, etc.) during appliance operation and
service (condensate trap, control replacement, etc.).

6
FRESH AIR FOR COMBUSTION
WARNING
Fire, and asphyxiation hazard. Carbon monoxide
is odorless, tasteless, clear colorless gas, which is
highly toxic. Air openings to combustion area must
not be obstructed. Follow all instructions to maintain
adequate combustion air. Failure to do so could result
in death or serious injury.
!
Provide combustion air and ventilation air in accordance
with the section “Air for Combustion and Ventilation,” of
the National Fuel Gas Code, ANSI Z223.1 / NFPA 54, or
applicable provisions of local building codes.
Provide make-up air where exhaust fans, clothes dryers,
and kitchen ventilation equipment interfere with proper
operation.
National Fuel Gas Code recognizes several methods
of obtaining adequate ventilation and combustion air.
Requirements of the authority having jurisdiction may
override these methods.
• Engineered Installations. Must be approved by
authority having jurisdiction.
• Mechanical Air Supply. Provide minimum of 0.35
cfm per Mbh for all appliances located within space.
Additional requirements where exhaust fans installed.
Interlock each appliance to mechanical air supply
system to prevent main burner operation when
mechanical air supply system not operating.
• All Indoor Air. Calculate minimum volume for all
appliances in space. Use a different method if
minimum volume not available.
A. Standard Method. Cannot be used if known air
infiltration rate is 0.40 air changes per hour. See
Table 1 for space with natural gas boiler only. Use
equation for multiple appliances and/or propane.
Volume ≥50 ft3x Total Input [Mbh]
B. Known Air Infiltration Rate. See Table 1 for
space with boiler only. Use equation for multiple
appliances. Do not use an air infiltration rate
(ACH) greater than 0.60.
Volume ≥21 ft3⁄ACH x Total Input [Mbh]
C. Refer to National Fuel Gas Code for opening
requirements between connected indoor spaces.
• All Outdoor Air. Provide permanent opening(s)
communicating directly or by ducts with outdoors.
A. Two Permanent Opening Method. Provide opening
commencing within 12 inches of top and second
opening commencing within 12 inches of bottom of
enclosure.
Direct communication with outdoors or
communicating through vertical ducts. Provide
minimum free area of 1 in² per 4 Mbh of total
input rating of all appliances in enclosure.
Communicating through horizontal ducts.
Provide minimum free area of 1 in² per 2
Mbh of total input rating of all appliances in
enclosure.
B. One Permanent Opening Method. Provide opening
commencing within 12 inches of top of enclosure.
Provide minimum clearance of 1 inch on sides/back
and 6 inches on front of boiler (does not supersede
clearance to combustible materials).
C. Refer to National Fuel Gas Code for additional
requirements for louvers, grilles, screens and air
ducts.
• Combination Indoor and Outdoor Air. Refer to National
Fuel Gas Code for application information.
Table 3 - Minimum Room Volume, Indoor Air Only*
Input Mbh Standard
Method
Known Air Infiltration Rate Method (Air Changes Per Hour)
0.1 0.2 0.3 0.4 0.5 0.6
75 3750 15750 7875 5250 3938 3150 2625
112.5 5625 23625 11813 7875 5906 4725 3938
150 7500 31500 15750 10500 7875 6300 5250
187 9350 39270 19635 13090 9818 7854 6545
255 11250 47250 23625 15750 11813 9450 7875
262.5 13125 55125 27563 18375 13781 11025 9188
299 14950 62790 31395 20930 15698 12558 10465
* Table values based on boiler only. Add volume for any additional appliances.

7
WARNING
Burn and scald hazard. Safety relief valve could
discharge steam or hot water during operation.
Install discharge piping per these instructions.
!
To avoid burns, scalding, or water damage due to discharge
of steam and/or hot water during operation, a discharge
line shall be installed to relief valve outlet connection.
Discharge line shall:
• connect to relief valve outlet and piped down to safe
point of disposal. Check local codes for maximum
distance from floor or allowable safe point of
discharge.
• be of pipe size equal to or greater than that of the
relief valve outlet over the entire length of discharge
line;
• have no intervening shutoff valve between safety
relief valve and discharge to atmosphere (do not
plug or place any obstruction in discharge line.
• terminate freely to atmosphere where any discharge
will be clearly visible and at no risk of freezing;
• allow complete drainage of the valve and the
discharge line;
• be independently supported and securely anchored
to avoid applied stress on the relief valve;
• be as short and straight as possible;
• terminate with plain end (not threaded);
• be constructed of material suitable for exposure to
temperatures of 375° F; or greater.
Refer to local codes and appropriate ASME Boiler
and Pressure Vessel Code for additional installation
requirements.
Figure 2
Check local codes
for maximum
distance from floor
or allowable safe
point of discharge.
Discharge Line
Safety Relief Valve
INSTALLATION - SYSTEM PIPING

8
INSTALLATION - SYSTEM PIPING
Consider near boiler piping as part of boiler for proper
water level control, and to produce dry steam. Correct near
boiler piping is crucial to proper operation of boiler and
heating system. Follow these recommendations carefully.
1. Place boiler in selected location, as near chimney as
possible.
2. Boiler is equipped with two 2-1/2” supply connections
and two 2-1/2” return connections, one each on both
left and right sides of the boiler. Unused connections
must be plugged with the 2-1/2” plugs (furnished).
3. Recommended near boiler piping for gravity return
systems is shown in Figure 3. This configuration uses
one supply and one return tapping. This setup can be
used on any size boiler in this series. The supply and
return connections may be piped both into the same
side (either left or right) or one into each side of the
boiler.
4. For installers choosing to use both supply tappings,
Figure 4A shows the correct way to pipe this system.
Figure 4B shows the wrong way to pipe a header with
two risers.
• Headers must be fitted with header offsets or swing
joints, or be equipped with expansion joints, so that
thermal expansion and contraction of the header will
not damage the boiler. Headers shall not be welded.
• System takeoffs from header must be between
equalizer and riser to header nearest equalizer.
System takeoffs must never be between two risers.
5. System takeoffs from header must never be
bullheaded. If steam main goes in two directions, there
must be two takeoffs from header, one for each main.
6. All boilers in gravity return systems must be equipped
with Hartford Loop as shown in Figures 3 and 4A.
7. When piping the vertical risers from boiler to header,
bottom of header must be minimum of 24 inches above
water level line on right side of boiler.
8. Steam riser(s) and header shall be 2-1/2” pipe size.
9. Equalizer line shall be minimum 1-1/2” pipe size.
10. Near boiler piping shall include 2-1/2” tee with plug
located on supply line as shown for skimming (i.e.
surface blowdown).
11. Near boiler piping shall include 1-1/2 ball valve in return
piping as shown for bottom blowdown and draining.
12. For gravity return systems, bottom of lowest steam
carrying pipe, be it dry return, or end of steam main,
must be at least 28” above normal water level line on
right side of boiler. This is known as “Dimension A.”
13. For pumped return systems, follow condensate pump or
boiler feed pump manufacturer’s instructions for proper
installation and hookup.
14. When connecting cold water supply to water inlet valve,
verify clean water supply is available. Install sand
strainer at pump when water supply is from well or
pump.
FOR USE WITH COOLING UNITS
A. Install boiler, when used in connection with
refrigeration system, so chilled medium is piped
in parallel with boiler with appropriate valves to
prevent chilled medium from entering boiler. See
Figure 5.
WARNING
Burn and scald hazard. Safety relief valve could
discharge steam or hot water during operation.
Install discharge piping per these instructions.
!

9
Figure 3 - Recommended Near Boiler Piping Using One Supply Tapping
INSTALLATION - SYSTEM PIPING

10
INSTALLATION - SYSTEM PIPING
Figure 4A - Recommended Near Boiler Piping Using One Supply Tapping

11
INSTALLATION - SYSTEM PIPING
Figure 5 - Chilled Water Piping
VALVES A & B OPEN FOR HEATING; CLOSE FOR COOLING
VALVES C & D CLOSE FOR HEATING; OPEN FOR COOLING
Figure 4B - Common Near Boiler Piping Mistakes

12
CHIMNEY AND VENT PIPE CONNECTION
For boilers for connection to gas vents or chimneys,
vent installations shall be in accordance with "Venting of
Equipment", of the National Fuel Gas Code, ANSI Z223.1/
NFPA 54, or applicable provisions of the local building
codes.
CHECK YOUR CHIMNEY
This is a very important part of your heating system. It
must be clean, right size, properly constructed and in
GOOD CONDITION.
Inspect chimney and verify that construction and size of
chimney meets all applicable provisions of the National Fuel
Gas Code and local building codes.
Figure 4 gives you an idea how boiler might be vented to
chimney. Note the height (HT) is measured from vent pipe
to top.
CONNECTING VENT DAMPER AND VENT CONNECTOR
Refer to Fig. 1 and Table 1 for size and location of vent
(flue opening). Use 28 gauge (minimum) galvanized pipe to
connect to chimney.
NOTICE
Damper blade on furnished vent damper has 1/2
square inch hole (approximately 3/4” diameter).
Boilers equipped with standing pilot, hole must be
left open.
Boilers equipped with intermittent ignition, hole
should be plugged by using plug supplied with vent
damper.
1. Position furnished vent damper on top of flue outlet
collar. Fasten damper securely to flue outlet collar
with sheet metal screws. Make sure damper blade has
clearance to operate inside of diverter. Do not modify
draft diverter or vent damper
Option:
Damper may be installed in any horizontal or vertical
position, closer to flue outlet collar preferred. Follow
diagrams - Figures 7, 8 and 9.
2. Install vent damper to service only single boiler for
which it is intended. Damper position indicator shall be
in visible location following installation. Locate damper
accessible for servicing.
3. Damper must be in open position when appliance main
burners are operating.
4. Boiler is equipped with factory wired harness that plugs
into vent damper. Thermostat must be connected to
black wires marked 24 volt thermostat on boiler.
5. Vent pipe must be same size as flue outlet collar.
6. Slope pipe up from boiler to chimney not less than 1/4”
per foot.
7. Run pipe as directly as possible with as few elbows as
possible.
8. Do not connect to fireplace flue.
9. End of vent pipe must be flush with inside face of
chimney flue. Use sealed-in thimble for chimney
connection.
10. Horizontal run should not be longer than 3/4 chimney
height (HT) (Fig. 6).
11. Fasten sections of vent pipe with sheet metal screws to
make piping rigid.
12. Support horizontal portions of vent system must be
supported to prevent sagging. Use stovepipe wires ev-
ery 5’ to support pipe from above.
13. If vent pipe must go through crawl space, double wall
vent pipe should be used.
14. Where vent pipe passes through combustible wall or
partition, use ventilated metal thimble. Thimble should
be 4 inches larger in diameter than vent pipe.
MINIMUM VENT PIPE CLEARANCE
Wood and other combustible materials must not be closer
than 6” from any surface of single wall metal vent pipe.
Listed Type B vent pipe or other listed venting systems shall
be installed in accordance with their listing.
REMOVING EXISTING BOILER FROM COMMON
VENTING SYSTEM
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 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.

13
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 the installation conforms with
the National Fuel Gas Code, ANSI Z223.1/NFPA 54.
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 Chapter 13 of the National Fuel
Gas Code, ANSI Z223.1/NFPA 54.
Vent connectors serving appliances vented by natural draft shall
not be connected into any portion of mechanical draft systems
operating under positive pressure.
CHIMNEY AND VENT PIPE CONNECTION
Figure 6 - Typical Masonry Chimney Requirements
VENT DAMPER OPERATION
Figure 7 - Horizontal Installation Figure 8 - Alternate Vent Damper Installation
TYPICAL INSTALLATION FOR VENT DAMPER
WARNING
Fire, and asphyxiation hazard. Carbon monoxide is odorless, tasteless, clear colorless gas, which is highly toxic.
Install vent damper to service single appliance for which it is intended only. Failure to do so could result in
death or serious injury.
!
1. Do not install vent damper on vent pipe curve.
2. Do not run wires near high temperature surfaces. Use stand-off brackets if necessary.

14
Check annually, vent damper and all flue product
carrying areas of appliance with particular attention
given to deterioration from corrosion or other
sources. If you see corrosion or other deterioration,
contact your heating contractor for repairs. Check
vent damper operation as follows:
1. When boiler is off, verify vent damper positions
indicator points to closed position, Fig. 9.
2. Turn thermostat or controller up to call for heat and
check vent damper indicator points to open position,
Fig. 8.
3. Turn thermostat or controller down again and check
damper position indicator returns to closed position.
4. If you have central air conditioning, set thermostat
to COOL and turn it down to call for cooling. Cooling
system should operate.
5. Return thermostat to desired position.
Inspect vent damper at least once a year by trained,
experienced service technician.
VENT DAMPER OPERATION
MANUAL OPERATION OF VENT DAMPER
Place vent damper in open position to permit burner
operation by using “HOLD DAMPER OPEN” switch,
located on damper controller. Thermostat will control
burner firing as before, while damper remains open.
DO NOT turn damper open manually or motor
damage will result. Set switch to “AUTOMATIC
OPERATION” to close vent damper during burner off
cycle.
For further information, and for vent damper
troubleshooting guide, refer to manual packaged with
vent damper.
Figure 9 - Vent Damper Position Indicator
GAS SUPPLY PIPING
General
• Use piping materials and joining methods acceptable
to authority having jurisdiction. In absence of such
requirements, National Fuel gas Code, ANSI Z223.1/
NFPA 54.
• Install field sourced manual main shutoff valve and
ground joint union.
• Size and install gas piping system to provide
sufficient gas supply to meet maximum input at not
less than minimum supply pressure. See Tables 4a &
4b.
NOTICE
Use two (2) wrenches when installing pipe to
gas valve. Boiler's gas valve can be damaged if
subjected to excessive torque.
• Support piping with hooks straps, bands, brackets,
hangers, or building structure components to prevent
or dampen excessive vibrations and prevent strain on
gas connection.
• Use thread (joint) compound (pipe dope) suitable for
liquefied petroleum gas.
• Provide sediment trap up stream of gas valve.
CAUTION
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
neighbor’s phone. Follow the gas supplier’s
instructions.
• If you cannot reach your gas supplier, call the fire
department.
!
!
DANGER
Fire Hazard. Do not use matches, candles, open
flames, or other methods providing ignition source.
Failure to comply will result in death or serious
injury.
!

15
Propane Installation
• Connections by licensed propane dealer only.
• Use two stage regulator provided by propane
supplier.
• Propane supplier should check piping.
Leak Check Gas Piping
Pressure test boiler and gas connection before placing
boiler in operation.
• Pressure test over 1/2 psig (3.5 kPa). Disconnect
boiler and its individual gas shutoff valve from gas
supply system.
• Pressure test at 1/2 psig (3.5 kPa) or less. Isolate
boiler from gas supply system by closing manual
gas shutoff valve.
• Locate leakage using gas detector, noncorrosive
detection fluid, or other leak detection method
acceptable to authority having jurisdiction. Do
not use matches, candles, open flames, or other
methods providing ignition source.
• Correct leaks immediately and retest.
GAS SUPPLY PIPING
Table - 4a Gas Pipe Sizes - Natural Gas
Length of
Pipe - Ft.
Pipe Capacity - BTU Per Hour Input
Includes Fittings
1/2" 3/4" 1" 1 -1/4"
20 92,000 190,000 350,000 625,000
40 63,000 130,000 245,000 445,000
60 50,000 105,000 195,000 365,000
Table - 4b Gas Pipe Sizes - Propane Gas
Length of
Pipe - Ft.
Pipe Capacity - BTU Per Hour Input
Includes Fittings
5/8" 3/4" 1/2" 3/4"
20 131,000 216,000 189,000 393,000
40 90,000 145,000 129,000 267,000
60 72,000 121,000 103,000 217,000
* Outside diameter
Length of pipe or tubing should be measured from gas meter or
propane second stage regulator.
Figure 10 - Gas Piping At Boiler

16
ELECTRICAL WIRING
ELECTRIC POWER SUPPLY
• All electrical work must conform to local codes, as well as
National Electrical Code, ANSI/NFPA-70.
• Run separate 115 volt circuit from separate overcurrent
protective device in your electrical service entrance panel,
should be 15 ampere circuit.
• Locate shut-off switch at boiler. Turn off during any
maintenance.
• Connect 115 volt electrical supply to primary leads on
24 volt transformer. Solder and tape or securely fasten
connections with wire nuts.
• Boiler must be electrically grounded in accordance
with requirements of authority having jurisdiction or,
in absence of such requirements, with the National
Electrical Code, ANSI/NFPA No. 70.
• Run 14 gauge or heavier copper wire from boiler to
grounded connection in service panel or properly driven
and electrically grounded ground rod.
THERMOSTAT INSTALLATION
Thermostat location has important effect on operation
of your boiler system. Follow Instructions Included With
Your Thermostat.
Locate thermostat about five feet above floor on inside
wall. Mount directly on wall or vertically mounted outlet
box. It should be sensing average room temperature, so
avoid following:
DEAD SPOTS:
Behind doors
Corners and alcoves
HOT SPOTS:
Concealed pipes
Fireplace
TV sets
Radios
Lamps
Direct sunlight
Kitchens
COLD SPOTS:
Concealed pipes or ducts
Stairwells - drafts
Doors – drafts
Unheated rooms on other side of wall
• Set heat anticipator at 0.4 amps for boilers equipped
with standing pilot.
• Connect 24 volt thermostat leads to two wires tagged
“24 volt thermostat” on boiler.
• Boilers with 67D-1 float type low water cut-off, two
wires are black. One wire is located on secondary of
24 volt transformer, second wire is located on pressure
limit control.
• Boilers with PS-802 probe type low water cut-off, one
wire is green and is located on terminal B of PS-802,
second wire is black and located on pressure limit
control.
ELECTRONIC THERMOSTATS
Certain types of electronic thermostats may lose their
memory or shut down.
A. 67D-1 float type low water cutoffs, this may occur
each time thermostat calls for heat, due to internal
circuit in vent damper.
B. PS-802 probe type low water cut off’s, this may oc-
cur each time low water cut off detects low water
condition. If this is case, isolation relay is required
for thermostat circuit.
C. 24 volt single pole single throw (SPST) normally
open (N.O.) relay is required, such as Honeywell
R8222A or equivalent. Wire as shown in Fig. 11A or
Fig. 11B.
VENT DAMPER
Boiler is equipped with factory wired harness with 4 pin
molex plug, that plugs into 4 pin molex receptacle inside
vent damper operator.
Connect vent damper for boiler to operation.
Wiring diagrams follow for various different models.
WARNING
Turn off electrical power at fuse box before making
any line voltage connections. Follow local electrical
codes.
!
WARNING
Label all wires prior to disconnection when servicing
controls. Wiring errors can cause improper and
dangerous operation. Verify proper operation after
servicing.
!

17
ELECTRICAL WIRING
Figure 11A - Isolation Relay Wiring For Steam
Boilers With Float Type Low Water Cut Off And Using
An Electronic Thermostat
Figure 11B - Isolation Relay Wiring For Steam
Boilers With Probe Type Low Water Cut Off And
Using An Electronic Thermostat

18
ELECTRICAL WIRING
Replace damaged wiring with type 105°C Thermoplastic wire or equivalent.
Figure 12 - Wiring Diagrams For Boilers With Probe Type Low Water Cut-Off
INTERMITTENT IGNITION
Shown PS802
Terminals
PS802 to CG400
Cross Reference
PS802 CG400
N2
H1
CP1
EP2
WA

19
ELECTRICAL WIRING
Figure 13 - Wiring Diagrams For Boilers With PS-802 Probe Type Low Water Cut-Off
STANDING PILOT
Replace damaged wiring with type 105°C Thermoplastic wire or equivalent.
Terminals
PS802 to CG400
Cross Reference
PS802 CG400
N2
H1
CP1
EP2
WA
Shown PS802

20
ELECTRICAL WIRING
Figure 14 - Wiring Diagrams For Boilers With 67D-1 Float Type Low Water Cut-Off
INTERMITTENT IGNITION
Replace damaged wiring with type 105°C Thermoplastic wire or equivalent.