Checking Transformer And Control Circuit; S-10B Capacitance Check; Checking Capacitor; S-15A Resistance Check - Amana GMSS9 Series Service Instructions Manual

SERVICING
Cooling Anticipator
The cooling anticipator is a small heater (resistor) in the
thermostat. During the "OFF" cycle it heats the bimetal
element helping the thermostat call for the next cooling cycle.
This prevents the room temperature from rising too high be-
fore the system is restarted. A properly sized anticipator
should maintain room temperature within 1 1/2 to 2 degrees.
The anticipator is fixed in the subbase and is not to be
replaced. If the anticipator should fail for any reason, the
subbase must be changed.
S-4 CHECKING TRANSFORMER AND CONTROL
CIRCUIT
A step-down transformer 120 volt primary to 24 volt second-
ary, 40 VA (Heating and Cooling Models) supplies ample
capacity of power for either operation.
HIGH VOLTAGE
D ALL
ISCONNECT POWER BEFORE SERVICING OR
CHANGING ANY ELECTRICAL WIRING.
F
SOURCES MAY BE PRESENT. AILURE TO DO SO MAY CAUSE
PROPERTY DAMAGE, PERSONAL INJURY OR DEATH.
1. Remove blower compartment door to gain access to
the thermostat low voltage wires located at the furnace
integrated control module.
2. Remove the thermostat low voltage wires at the furnace
integrated control module terminals.
With Power On (and Door Interlock Switch closed):
WARNING
L
INE VOLTAGE NOW PRESENT
3. Use a voltmeter, check voltage across terminals R
and C. Must read 24 VAC.
4. No voltage indicates faulty transformer, open fuse,
bad wiring, bad splice, or open door interlock switch.
5. Check transformer primary voltage at incoming line
voltage connections, fuse, splices, and blower door
interlock switch.
6. If line voltage is available to the primary side of trans-
former and not at secondary side, the transformer is
inoperative. Replace.
7. After completing check and/or replacement of trans-
former and check and/or repair of control circuit, rein-
stall blower compartment door.
8. Turn on electrical power and verify proper unit opera-
tion.
46
WARNING
M
ULTIPLE POWER

S-10B CAPACITANCE CHECK

WARNING
L
INE VOLTAGE NOW PRESENT
S-15

CHECKING CAPACITOR

The direct drive motors are of the permanent split capacitor
design. A run capacitor is wired across the auxiliary and a
portion of the main windings. The capacitors primary func-
tion is to reduce the line current while greatly improving the
torque characteristics of a motor. This is accomplished by
using the 90° phase relationship between the capacitor cur-
rent and voltage in conjunction with the motor windings so
that the motor will give two phase operation when connected
to a single phase circuit. The capacitor also reduces the
line current to the motor by improving the power factor to
the load.
D
ISCHARGE CAPACITOR THROUGH A 20 TO 30 OHM RESISTOR
BEFORE HANDLING.
Two quick ways to test a capacitor are a resistance and a
capacitance check. Refer to the next two figures for proper
meter connections for the resistance and capacitance test-
ing of the capacitor.

S-15A RESISTANCE CHECK

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 blower compartment door to gain access to
capacitor.
2. Discharge capacitor and remove wire leads.
3. Set an ohmmeter on its highest ohm scale and connect
the leads to the capacitor.
a. Good Condition - indicator swings to zero and
slowly returns toward infinity.
b. Shorted - indicator swings to zero and stops there
- replace.
c. Open - no reading - replace. Reverse leads. Check
again no reading - replace.
d. Reverse leads and recheck.
WARNING
WARNING