SERVICING
S-4 CHECKING TRANSFORMER AND CONTROL CIRCUIT
A
WARNING
1.Remove control panel cover or etc. to gain access to trans- former.
With power ON:
S-8 CHECKING CONTACTOR CONTACTS
DISCONNECT POWER SUPPLY BEFORE SERVICING.
SINGLE PHASE
1.Disconnect the wire leads from the terminal (T) side of the contactor.
2.With power ON, energize the contactor.
LINE VOLTAGE NOW PRESENT.
T2 
T1
LINE VOLTAGE NOW PRESENT.
VOLT/OHM
METER
CC
2. | Using a voltmeter, check voltage across secondary voltage |
| side of transformer (R to C). |
3. | No voltage indicates faulty transformer, bad wiring, or bad |
| splices. |
4. | Check transformer primary voltage at incoming line voltage |
| connections and/or splices. |
5If line voltage is present at the primary voltage side of the transformer and 24 volts is not present on the secondary side, then the transformer is inoperative. Replace.
S-7 CHECKING CONTACTOR AND/OR RELAYS
The compressor contactor and other relay holding coils are wired into the low or line voltage circuits. When the control circuit is energized the coil pulls in the normally open contacts or opens the normally closed contacts. When the coil is de- energized, springs return the contacts to their normal position.
DISCONNECT POWER SUPPLY BEFORE SERVICING.
1.Remove the leads from the holding coil.
2.Using an ohmmeter, test across the coil terminals.
If the coil does not test continuous, replace the relay or con- tactor.
L2 L1
Ohmmeter for testing holding coil
Voltmeter for testing contacts
TESTING COMPRESSOR CONTACTOR
(Single Phase)
3.Using a voltmeter, test across terminals.
A.L1 to L2 - No voltage. Check breaker or fuses on main power supply. If voltage present, proceed to step B.
B.T1 to T2 - Meter should read the same as L1 to L2 in step A. If voltage readings are not the same as step A, replace contactor.
THREE PHASE
Using a voltmeter, test across terminals:
A.
B.
24
