Checking Contactor And/Or Relays; Checking Contactor Contacts; Checking Fan Relay Contact - Daikin DCH048 Series Service Instructions Manual

SERVICING
S-7 CHECKING CONTACTOR AND/OR RELAYS
HIGH VOLTAGE!
Disconnect ALL power before servicing
or installing this unit. Multiple power
sources may be present. Failure to do so
may cause property damage, personal injury
or death.
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.
NOTE: Most single phase contactors break only one side of
the line (L1), leaving 115 volts to ground present at most
internal components.
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
contactor.
S-8 CHECKING CONTACTOR CONTACTS
HIGH VOLTAGE!
Disconnect ALL power before servicing
or installing this unit. Multiple power
sources may be present. Failure to do so
may cause property damage, personal injury
or death.
1. Disconnect the wire leads from the terminal (T) side of the
contactor.
2. With power ON, energize the contactor.
3. 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
Ohmmeter for testing holding coil
Voltmeter for testing contacts
TESTING COMPRESSOR CONTACTOR
(ThreePhase)
S-9 CHECKING FAN RELAY CONTACTS
DCG:
The fan relays are incorporated into the control board. See
section S-313 for checking control board for single phase gas
models.
For 3 phase and belt drive models, the procedure for testing
the fan relay contacts will be the same as checking the
compressor contactor contacts (See section S-8).
DCC:
The Electronic Blower Time Delay Relay is used on PSC and
belt driven models.
HIGH VOLTAGE!
Disconnect ALL power before servicing
or installing this unit. Multiple power
sources may be present. Failure to do so
may cause property damage, personal injury
or death.
Checking EBTDR High Voltage Contacts
1. With power off, remove wires from terminals NC, COM,
and NO.
2. Using a VOM, check for resistance from NO to COM.
Should read open. Next, check for resistance from NC to
COM. Should read closed.
3. If not as above, replace EBTDR.
T3 T2 T1
CC
L3 L2 L1
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