Checking Transformer & Control Circuit; Checking Contactor And/Or Relays; Checking Contactor Contacts - Daikin DCG Series Service Instructions Manual

SERVICING
S-4 CHECKING TRANSFORMER
AND CONTROL CIRCUIT
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.
A step-down transformer (either 208-240, 460 or 575 volt pri-
mary to 24 volt secondary) is provided with each unit. This
allows ample capacity for use with resistance heaters.
WARNING
Disconnect ALL power before servicing.
1. Remove control panel cover to gain access to trans-
former.
With power ON:
WARNING
Line Voltage now present.
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.
5 If line voltage available at primary voltage side of trans-
former and wiring and splices good, transformer is inop-
erative. Replace.
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
SINGLE PHASE
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.
VOLT/OHM
METER
Ohmmeter for testing holding coil
Voltmeter for testing contacts
TESTING COMPRESSOR CONTACTOR
(Single Phase)
3. Using a voltmeter, test across terminals.
A. L1 - L2 - No voltage. Check breaker or fuses on main
power supply.
B. L2 - T1 - No voltage indicates CC1 contacts open.
If a no voltage reading is obtained - replace the contactor.
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..
T2 T1
CC
L2 L1
47