Goodman MH8 Installation Instructions Manual page 28

S - P
TART UP ROCEDURE AND
M S S
ODELS USING INGLE TAGE
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).
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.
A
DJUSTMENT
G V
AS ALVES
Inlet Pressure
Tap
INLET
Outlet Pressure
Tap
Pressure Regulator
(under cap screw)
Outlet
Pressure
Tap
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.
Inlet Gas Supply Pressure
Natural Gas Minimum:5.0" W.C. Maximum :10.0" W.C.
Propane Gas Minimum:11.0" W.C. Maximum :13.0" W.C.
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 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).
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.
M T S
ODELS USING WO TAGE
T
O PREVENT UNRELIABLE OPERATION
GAS MANIFOLD PRESSURE
. O
PLATE NLY MINOR ADJUSTMENTS
THE GAS VALVE PRESSURE
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.
28
G V
AS ALVES
CAUTION
OR EQUIPMENT DAMAGE
MUST BE AS SPECIFIED ON THE UNIT
SHOULD BE MADE BY
.
REGULATOR
,
THE
RATING
ADJUSTING