S-308 Checking Hot Surface Ignitor; S-309 Checking For Flashback; S-310 Checking Pressure Switch - Maytag Amana GMES9 Series Service Instructions Manual

SERVICING
HIGH VOLTAGE
D ALL
ISCONNECT ELECTRICAL POWER AND SHUT OFF GAS
SUPPLY BEFORE SERVICING OR INSTALLING THIS UNIT.
M
ULTIPLE POWER SOURCES MAY BE PRESENT.
DO SO MAY CAUSE PROPERTY DAMAGE, PERSONAL INJURY OR DEATH.
7. Turn on gas to furnace and check for leaks. If leaks are
found, repair and then reinstall burner compartment door.
8. Turn on electrical power and verify proper unit operation.
Gas Valve
On/Off
Selector
Switch
OUTLET
Pressure Regulator
Adjustment
(Under Cap Screw)
White-Rodgers Model 36J22 (Single-Stage)
Inlet
Pressure
Tap
Gas Valve On/Off
Selector Switch
Honeywell Model VR8215
Manifold Gas Pressure
Gas Rate
High Stage 9.7 to 10.3" w.c. 10.0" w.c.
Propane Gas
Low Stage 5.7 to 6.3" w.c. 6.0" w.c.

S-308 CHECKING HOT SURFACE IGNITOR

Single stage furnaces use a 115 volt silicon carbide igniter
(p/n 0130F00008) with 17-second warm up time.
D ALL
ISCONNECT POWER BEFORE SERVICING.
1. Remove burner compartment door to gain access to the
ignitor.
2. Ignitor cool - approximately 70 - 77°F.
3. Disconnect the ignitor from the Ignition Control.
4. Using an ohmmeter measure the resistance of the ignitor:
-at room temperature a normal reading will be 37 - 68
ohms.
5. Reconnect ignitor.
52
WARNING
F
AILURE TO
Inlet Pressure
Tap
INLET
Outlet Pressure
Tap
Pressure Regulator
(under cap screw)
Outlet
Pressure
Tap
Range Nominal
WARNING
L
INE VOLTAGE NOW PRESENT
6. Place unit in heating cycle, measure current draw of ignitor
during preheat cycle.

S-309 CHECKING FOR FLASHBACK

Flashback will also cause burning in the burner venturi, but is
caused by the burning speed being greater than the gas-air
flow velocity coming from a burner port.
Flashback may occur at the moment of ignition, after a burner
heats up or when the burner turns off. The latter is known
as extinction pop.
Since the end results of flashback and delayed ignition can
be the same (burning in the burner venturi) a definite attempt
should be made to determine which has occurred.
If flashback should occur, check for the following:
1. Improper gas pressure - adjust to proper pressure (See
S-307 CHECKING GAS PRESSURE)..
2. Check burner for proper alignment and/or replace burner.
3. Improper orifice size - check orifice for obstruction.

S-310 CHECKING PRESSURE SWITCH

The pressure control is a safety device to prevent the com-
bustion cycle from occurring with inadequate venting caused
by a restricted or blocked vent pipe.
HIGH VOLTAGE
D ALL
ISCONNECT POWER BEFORE SERVICING OR
M
INSTALLING THIS UNIT. ULTIPLE POWER SOURCES MAY
F
BE PRESENT. AILURE TO DO SO MAY CAUSE PROPERTY
DAMAGE, PERSONAL INJURY OR DEATH.
1. Remove burner compartment door to gain access to
pressure switch(es).
2. Remove wires from the pressure switch(es) electrical
terminals.
3. Remove the pressure control hose from the control and
interconnect with an inclined manometer as shown in the
following figures.
With a call for heat and the inducer running, check across
the pressure switch contacts with an ohm meter. If the con-
tacts are not closed, compare the negative reading on the
inclined manometer with the rating on the pressure switch to
determine whether the switch is defective or if the negative
pressure is inadequate to close the switch.
* * *
M
1
O P 3 *
F F
C 2
O N
*
* *
COIL COVER
PRESSURE SWITCH
INDUCED
DRAFT
BLOWER
Blower Pressure Switch
Negative Pressure Measurement
WARNING
WARNING
INDUCED DRAFT BLOWER
PRESSURE SWITCH
PRESSURE SWITCH
HOSE
OPEN TO
ATMOSPHERE
1/4" TEE
INCLINED MANOMETER
HOSE TO INDUCED
DRAFT BLOWER TAP