GMS8 Installation Manual

26
Turn inlet pressure test screw in to seal pressure port
(clockwise, 7 in-lb minimum).
12. Retest for leaks. If bubbles form, shut down gas and repair
leaks immediately.
13. Turn ON electrical power and gas supply to the system.
14. Turn valve switch ON.
MODELS USING TWO STAGE GAS VALVES
T O PREVENT UNRELIABLE OPERATION OR EQUIPM ENT DAM AGE , THE
GAS M ANIFOLD PRESSURE M UST BE AS SPECIFIED ON THE UNIT RATING
PLATE . O NLY M INOR ADJUSTM ENTS SHOULD BE M ADE BY ADJUSTING
THE GAS VALVE PRESSURE REGULATOR .
CAUTION
NOTE: When removing a valve adjustment screw or a pressure
Tap, use a T-25 Torx or 3/616” flathead screwdriver. DO NOT USE
POW ER TOOLS.
The line pressure supplied to the gas valve must be within the
range specified below. The supply pressure can be measured at
the gas valve inlet pressure Tap or at a hose fitting installed in the
gas piping drip leg. The supply pressure must be measured with
the burners operating. To measure the gas supply pressure, use
the following procedure.
INLET OUTLET
Gas Valve On/Off
Selector Switch
White-Rodgers Model 36J54 (Two-Stage)
Inlet
Pressure
TAP
Low Fire
Regulator
Adjust
M a
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t
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r
M
a
n
o m
e
t
e r
H o
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e
High Fire Regulator
Adjust
Regulator
Vent
Outlet
Pressure Boss
Open to
Atmosphere
O n
/ O f
f
S
w i
t
c
h
H
i
g
h F
i
r e
C o i
l
T
e r m
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( H
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)
C o
a x
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C
o
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T
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( M
)
Common
Terminal(C)
White-Rodgers Model 36J54 Connected to Manometer
Gas Valve On/Off
Selector Switch
Inlet
Pressure
Ta p
Pressure Regulator
(under cap screw)
Outlet
Pressure
Ta p
Honeywell Model VR8215 (Single-Stage)
1. Turn OFF gas to furnace at the manual gas shutoff valve
external to the furnace.
2. Turn OFF all electrical power to the system.
3. Inlet pressure tap connections:
a. Honeywell Valve:
Remove the inlet pressure Tap plug. Install an 1/8” NPT
hose barb fitting into the outlet pressure tap.
b. White-Rodgers valve:
Back inlet pressure test screw (inlet pressure Tap out one
turn (counterclockwise, not more than one turn).
4. Attach a hose and manometer to the outlet pressure barb
fitting (Honeywell valve) or inlet pressure Tap White-
Rodgers valve).
5. Turn ON the gas supply.
6. Turn On power and close thermostat “ R” and “ W” contacts
to provide a call for heat.
7. Using a leak detection solution or soap suds, check for
leaks at outlet pressure Tap plug (Honeywell valve) or screw
(White-Rodgers valve). Bubbles forming indicate a leak.
SHUT OFF GAS AND REPAIR ALL LEAKS IM MEDIATELY!
8. M easure the gas supply pressure with burners firing.
Adjust supply pressure using the Inlet Gas Supply Pressure
table shown below. If supply pressure reading differs from
the table, make necessary adjustments to pressure
regulator, gas piping size, etc., and/ or consult with local
gas utility.
Natural Gas Minimum: 4.5" w.c. Maximum: 10.0" w.c.
Propane Gas Minimum: 11.0" w.c. Maximum: 13.0" w.c.
INLET GAS SUPPLY PRESSURE
9. Turn OFF all electrical power and gas supply to the system.
10. Remove the manometer hose from the hose barb fitting
or inlet pressure Tap.
11. Replace inlet pressure tap:
a. Honeywell valve:
Remove the 1/8” NPT hose barb fitting from the inlet
pressure tap. Replace the inlet pressure Tap plug and
seal with a high quality thread sealer.
b. White-Rodgers valve: