Gas Manifold Pressure Measurement And Adjustment; Disconnect Electrical Power And Shut Off Gas Supply; Gas Valve Adjustment Procedures For Guis/Gcis/Guiv Two-Stage Furnaces; Natural Gas Adjustments - Amana GUIA070A30 Service Instructions Manual

Gas Manifold Pressure Measurement and Adjustment

CAUTION
To prevent unreliable operation or equipment dam-
age, the gas manifold pressure must be as specified
on the unit rating plate. Only minor adjustments should
be made by adjusting the gas valve pressure regula-
tor.
Only small variations in gas pressure should be made by
adjusting the gas valve pressure regulator. The manifold pres-
sure must be measured with the burners operating. To mea-
sure and adjust the manifold pressure, use the following pro-
cedure.
WARNING

Disconnect Electrical Power and Shut Off Gas Supply:

1. After turning off gas to furnace at the manual gas shutoff
valve external to the furnace, remove burner compart-
ment 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
as shown in the following figure.
Gas Valve Control
WR
ON/Off Switch
M 1
P 3
O
F
INLET F
C 2
ON
Inlet Pressure Tap
(Side of Valve) Outlet (Manifold) Pressure Tap
Pressure Regulator Adjustment
(Under Cap Screw)
Measuring Manifold Gas Pressure
(Gas Valve Tap)
WARNING
LINE VOLTAGE NOW PRESENT.
3. Turn ON the gas and electrical power supply and oper-
ate the furnace.
4. Measure gas manifold pressure with burners firing. Ad-
just manifold pressure using the table below.
Manifold Gas Pressure
Natural Gas
Propane Gas
SERVICING
Manometer Hose
OUTLET
Open to
Atmosphere
(Side of Valve)
Manometer
3.5" w.c.
10.0" w.c.
The final manifold pressure must not vary more than ± 0.3 "
w.c. 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. To adjust the gas valve pressure regulator, remove the
regulator cap.
6. Turn the adjustment screw clockwise to increase the
pressure, or counterclockwise to decrease the pressure.
7. Securely replace the regulator cap.
WARNING
Disconnect Electrical Power and Shut Off Gas Supply:
8. Disconnect manometer after turning off gas at manual
shutoff valve. Reinstall gas valve outlet pressure tap plug
before turning on gas to furnace.
9. Turn on gas to furnace and check for leaks. If leaks are
found, repair and then reinstall burner compartment door.
10. Turn on electrical power and verify proper unit operation.
Gas Valve Adjustment Procedures for GUIS/GCIS/GUIV
Two-Stage Furnaces

Natural Gas Adjustments

WARNING
Disconnect Electrical Power and Shut Off Gas Supply:
1. After turning off gas to furnace at the manual gas shutoff
valve external to the furnace, remove burner compart-
ment 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 previous Measuring Manifold Gas Pressure
figure for proper connection.
WARNING
LINE VOLTAGE NOW PRESENT.
3. Turn ON the gas and electrical power supply and oper-
ate the furnace.
4. Adjust the high stage regulator to required manifold pres-
sure setting.
5. Reinstall high stage cap screw and recheck manifold
pressure setting with cap on.
6. Adjust low stage regulator to required manifold pressure
setting.
7. Reinstall low stage cap screw and recheck manifold pres-
sure setting with cap on.
87
Rev. 2