Service manual

SERVICING
76
3. Using a voltmeter, test across terminals.
A. L2 - T1 - No voltage indicates CC1 contacts open.
If a no voltage reading is obtained - replace the contactor.
VOLT/OHM
METER
T1
T2
L1L2
CC
Ohmmeter for testing holding coil
Voltmeter for testing contacts
TESTING COMPRESSOR CONTACTOR
(Single Phase)
THREE PHASE
Using a voltmeter, test across terminals:
A. L1-L2, L1-L3, and L2-L3 - If voltage is present,
proceed to B. If voltage is not present, check breaker
or fuses on main power supply..
B. T1-T2, T1-T3, and T2-T3 - If voltage readings are not
the same as in "A", replace contactor.
VOLT/OHM
METER
CC
Ohmmeter for testing holding coil
Voltmeter for testing contacts
T1
L1
T3
L3
T2
L2
TESTING COMPRESSOR CONTACTOR
(Three-phase)
S-8A CHECKING UNITARY (UC) CONTROL
COMPRESSOR CONTACTOR/RELAY
CONTACTS
WARNING
Disconnect ALL power before servicing.
1. Connect voltmeter to lugs (L2) and (C).
2. With power ON, provide a call for cool or heat pump to
energize the on-board compressor contactor/relay.
WARNING
Line Voltage now present.
3. Measure voltage across on-board compressor contactor/
relay contacts.
A. No voltage indicates the contacts are closed and the
contactor/relay is functioning properly.
B. A reading of approximately half of the supply voltage
(example: 115VAC for 230VAC) indicates the relay is
open. Replace UC control if relay does not close.
NOTE: The unitary (UC) control has a built-in short cycle
delay. Ensure short cycle delay has elapsed before making
voltage measurements.
S-9 CHECKING FAN RELAY CONTACTS
HIGH VOLTAGE!
Disconnect ALL power before servicing
or installing. Multiple power sources
may be present. Failure to do so may
cause property damage, personal injury
or death.
1. Disconnect wire leads from terminals 2 and 4 of Fan Relay
Cooling and 2 and 4, 5 and 6 of Fan Relay Heating.
2. Using an ohmmeter, test between 2 and 4 - should read
open. Test between 5 and 6 - should read continuous.
3. With power ON, energize the relays.
WARNING
Line Voltage now present.
1
2
3
4
5
OHMMETER
TESTING FAN RELAY
4. Using an ohmmeter, test between 2 and 4 - should read
continuous . Test between 5 and 6 - should read open.
5. If not as above, replace the relay.
FAN RELAY CONTACTS - UNITARY (UC) CONTROL
Applies to ASXC/ASZC and DSXC/DSZC Models