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SERVICING
A step-down transformer (either 208-240, 460 or 575 volt
primary 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
transformer and wiring and splices good, transformer
is inoperative. 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 con-
trol 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, pro-
ceed 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.
T2
T1
CC
L2
L1
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