Carrier 38SE - Manual (Page 9)

CONTROL CIRCUIT TROUBLESHOOTING CHART
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fofs wvi om m xiix^ |b«sC8!^ of isssancaof higff volisga).
Before attempting any corrective action, wait 8 minutes after power is supplied to permit CPCS time delay period to end. If control circuit is
broken and unit has no time delay (or if time deiay is over 8 minutes), repiace CPCS board.
CONTACTS CLOSE
iMMEDiATELY, UNiT----------►
DOES NOT RUN
CONTACTS WON'T STAY
CLOSED. OR, CONTACTS
OPEN BEFORE ROOM ’
THERMOSTAT iS
SATiSFiED
VOLTAGE LOW OR_
NO VOLTAGE
LOOSE CONNECTIONS-
OR IMPROPER WIRING
VOLTAGE LOW OR.
NO VOLTAGE
VOLTAGE LOW OR­
NO VOLTAGE
VOLTAGE CORRECT-
VOLTAGE IS LOWER.
THAN 20 VOLTSt
VOLTAGE IS LOWER.
THAN 20 VOLTSt
VOLTAGE IS LOWER
THAN 20 VOLTSt
CPCS Board and control circuit func­
tion Check compressor, run capacitor,
start gear and internal compressor
protection
____ __________
Check system pressures and current
draw
Obtain correct voltage
Repair connection or correct wiring
Replace transformer
Replace transformer
Replace contactor
Check indoor unit power. indoor
transformer, thermostat or control
relay
System pressure too high or bad high-
pressure switch
System pressure too low, bad low-
pressure switch or open internal pro­
tector (IP)
L| L2
I—nfTWWOlWi---- 1
2SVA
TYPICAL CONTROL CIRCUIT INDOOR UNIT TRANSFORMER
O
CPCS Receptacle
o Component Connections
tVoltage reading less than 20 volts may result from feedback circuit.
0—^—0—
TRIAC