Goodman AMES960403BU AA, Service And Troubleshooting

Page: 22 / 29

SERVICING
22
Gas Manifold Pressure Measurement and
Adjustment
T
O P REVE NT U N RE L I ABL E OP ER AT I ON O R EQUI P ME NT DA M AG E , TH E
GA S M AN I FOLD P RESSURE MUS T B E A S S P E C I F IE D ON TH E U N I T
R AT I NG PLAT E .
O
NLY MI NO R AD JUS T ME NT S S HO U LD B E M AD E BY
AD JUS T I NG TH E GA S V AL VE P RESSURE RE G U LATO R .
CAUTION
NOTE: Use apapter kit #0151K00000S to measure gas
pressure on White-Rodgers 36J22 gas valves.
Only small variations in gas pressure should be made by
adjusting the gas valve pressure regulator. The manifold
pressure must be measured with the burners operating. To
measure and adjust the manifold pressure, use the following
procedure.
WARNING
H I GH V OLTAG E
D
IS CONN E CT
ALL
E L E CT RI CAL PO WER AND S H U T OFF GA S SU PPLY
B E FO RE SERVI C I NG O R I N S TALL I NG.
1. After turning off gas to furnace at the manual gas shutoff
valve external to the furnace, remove burner compartment
door to gain access to the gas valve.
2. Connect a calibrated water manometer (or appropriate
gas pressure gauge) at the gas valve outlet pressure
tap. Refer to Measuring Gas Pressure: Single Stage
Valves figure for single stage valve outlet pressure tap
connections.
L
I N E V OLTAG E NO W P RESE NT
WARNING
3. Turn ON the gas and electrical power supply and operate
the furnace.
4. Measure gas manifold pressure with burners firing. Adjust
manifold pressure using the table below.
Manifold Gas Pressure
Natural Gas 2.8 -3.2" w.c.
The final manifold pressure must not vary from the above
specified pressures. Any necessary major changes in gas flow
rate should be made by changing the size of the burner orifice.
5. White-Rodgers 36J22 Valves:
a. Back outlet pressure test screw (inlet/outlet pressure
boss) out one turn (counterclockwise, not more than
one turn).
b. Attach a hose and manometer to the outlet pressure
outlet pressure boss.
c. Turn ON the gas supply.
d. Turn on power and close thermostat “R” and “W”
contacts to provide a call for low stage heat.
e. Measure the gas manifold pressure with burners firing.
Adjust manifold pressure using the Manifold Gas
Pressure table shown below.
f. Remove regulator cover screw from the outlet pressure
regulator adjust tower and turn screw clockwise to
increase pressure or counterclockwise to decrease
pressure. Replace regulator cover screw.
i. Turn off all electrical power and gas supply to the
system.
j. Remove the manometer hose from the hose barb fitting
or outlet pressure boss.
k. Turn outlet pressure test screw in to seal pressure port
(clockwise, 7 in-lb minimum).
WARNING
H I GH V OLTAG E
D
IS CONN E CT
ALL
E L E CT RI CAL PO WER AND S H U T OFF GA S
SU PPLY B E FO RE SERVI C I NG O R I N S TALL I NG TH IS U N I T.
M
U LT I PL E PO WER S O UR C ES M AY B E P RESE NT.
F
A I L URE TO
DO S O M AY CA USE P R OP ER TY DA M AG E , P ERS ONAL I N JUR Y O R D E ATH.
6. Turn on gas to furnace and check for leaks. If leaks are
found, repair and then reinstall burner compartment door.
7. Turn on electrical power and verify proper unit operation.
Pressure Regulator
Adjustment
(Under Cap Screw)
Gas Valve
On/Off
Selector
Switch
INLET OUTLET
Inlet Pressure
Tap
Outlet Pressure
Tap
WARNING
H I GH V OLTAG E
D
IS CONN E CT
ALL
E L E CT RI CAL PO WER AND S H U T OFF GA S SU PPLY
B E FO RE SERVI C I NG O R I N S TALL I NG.
D
IS CONN E CT
ALL
PO WER B E FO RE SERVI C I NG.
WARNING
CHECKING HOT SURFACE IGNITOR
120V Silicon Nitride Ignitor - ULN furnaces use a 120V
silicone nitride igniter, part #0130F00717. The normal
operating temperature is approximately 2156°F - 2678°F. At
room temperature the igniter ohm reading should be from
20-100 ohms.