Goodman MH8 Installation Instructions Manual page 26

S - P
TART UP ROCEDURE AND
HIGH VOLTAGE !
D
ISCONNECT ALL POWER BEFORE
. M
INSTALLING THIS UNIT ULTIPLE
. F
BE PRESENT AILURE TO DO
,
DAMAGE PERSONAL INJURY
M S S
ODELS USING INGLE
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 mea-
sured with the unit OFF. To measure inlet pressure, use the
following procedure.
Gas Valve
On/Off
Selector
Switch
OUTLET
Pressure Regulator
Adjustment
(Under Cap Screw)
White-Rodgers Model 36G22
Inlet
Pressure
Tap
Gas Valve On/Off
Selector Switch
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 VR8215 Valve:
Remove the inlet pressure boss plug. Install an 1/8"
NPT hose barb fitting into the outlet pressure tap.
b. White-Rodgers 36G22 valve:
Back inlet pressure test screw (inlet pressure boss)
out one turn (counterclockwise, not more than one
turn).
A
DJUSTMENT
WARNING
SERVICING OR
POWER SOURCES MAY
SO MAY CAUSE PROPERTY
.
OR DEATH
G V
TAGE AS ALVES
Inlet Pressure
Outlet Pressure
Tap
Pressure Regulator
(under cap screw)
4. Attach a hose and manometer to the outlet pressure
barb fitting (Honeywell valve) or inlet pressure boss (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 boss plug (Honeywell valve) or
screw (White-Rodgers valve). Bubbles forming indicate
a leak. SHUT OFF GAS AND REPAIR ALL LEAKS
IMMEDIATELY!
8. Measure 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
Tap
Propane Gas
9. Turn OFF all electrical power and gas supply to the
system.
INLET
10. Remove the manometer hose from the hose barb fitting
or inlet pressure boss.
11. Replace inlet pressure tap:
a. Honeywell VR8215 valve:
Remove the 1/8" NPT hose barb fitting from the inlet
pressure tap. Replace the inlet pressure boss plug
and seal with a high quality thread sealer.
b. White-Rodgers 36G22 valve:
Turn inlet pressure test screw in to seal pressure port
(clockwise, 7 in-lb minimum).
Outlet
Pressure
12. Retest for leaks. If bubbles form, shut down gas and
Tap
repair leaks immediately.
13. Turn ON electrical power and gas supply to the system.
14. Turn valve switch ON.
M
ODELS USING
T
O PREVENT
GAS MANIFOLD
. O
PLATE NLY
THE GAS VALVE
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 boss or at a hose fitting installed
in the gas piping drip leg. The supply pressure must be mea-
sured with the burners operating. To measure the gas supply
pressure, use the following procedure.
26
Inlet Gas Supply Pressure
Minimum:5.0" W.C. Maximum :10.0" W.C.
Minimum:11.0" W.C. Maximum :13.0" W.C.
T S G V
WO TAGE AS ALVES
CAUTION
UNRELIABLE OPERATION OR EQUIPMENT
PRESSURE MUST BE AS SPECIFIED
MINOR ADJUSTMENTS SHOULD
.
PRESSURE REGULATOR
,
DAMAGE THE
ON THE UNIT RATING
BE MADE BY ADJUSTING