Carrier 50MQ - Manual (Page 11)

TROUBLESHOOTING CHART - HEATING CYCLE
NO HEATING OR
INSUFFICIENT HEATING
CONTACTOR
OPEN
OPENING IN
POWER CIRCUIT
DEFECTIVE LOW
VOLTAGE
TRANSFORMER
REMOTE CONTROL
CENTER DEFECTIVE
CONTROL RELAY
COIL OR CONTACTS
DEFECTIVE
COMPRESSOR
WILL NOT RUN COMPRESSOR RUNS
BUT CYCLES ON
COMPRESSOR RUNS -
INSUFFICIENT HEATING
CONTACTOR
CLOSED
COMPRESSOR
POWER SUPPLY
OPEN
LOOSE LEADS
AT COMPRESSOR
FAULTY START
CAPACITOR OR RELAY
SINGLE PHASE ONLY
COMPRESSOR
STUCK
REVERSING VALVE
RELAY DEFECTIVE
CONTACTOR COIL
OPEN OR SHORTED
KLIXON OR OVER­
LOAD DEFECTIVE
INTERNAL LOW LINE VOLTAGE
OVERLOAD OR UNBALANCED
3-PHASE LINE
DIRTY FILTERS
OR INDOOR COIL DEFECTIVE RUN
CAPACITOR
(SINGLE PHASE)
INDOOR FANS
CYCLING ON
OVERLOAD
COMPRESSOR
BEARINGS
1
DEFECTIVE FAN
MOTOR CAPACITOR HIGH LOAD
CONDITION
1
LOOSE LEADS AT
FAN MOTOR OVERCHARGE OR
NONCONDENSABLES
1 ■■ "
FAN MOTOR
BURNED OUT REVERSING VALVE
JAMMED IN MID­
POSITION
LOW SUCTION
LOW HEAD
1
OUTDOOR FAN
STOPPED
—1 p
OUTDOOR fan
RUNNING
LOOSE LEADS AT
OUTDOOR FAN
MOTOR
INTERNAL FAN
MOTOR KLIXON
OPEN
FAN MOTOR
BURNED OUT
DEFROST RELAY
N.C. CONTACTS
OPEN
DAMAGED
REVERSING VALVE
RESTRICTION IN
DISCHARGE LINE
OVERCHARGE OR
NONCONDENSABLES
IN SYSTEM
RESTRICTED
LIQUID LINE
ACCU RATER '
RESTRICTED OR
ICE CLOGGED
UNDERCHARGED
OUTDOOR COIL
^ DIRTY
OUTDOOR COIL
HEAVILY FROSTED
DEFECTIVE DEFROST
THERMOSTAT
DEFROST THERMOSTAT
IN POOR PHYSICAL
CONTACT WITH LINE
DEFECTIVE DEFROST
RELAY OR DEFROST
TIMER
REVERSING VALVE
STUCK
BAD ELECTRICAL CON-
NECTiON ANYWHERE IN
DEFROST CIRCUIT
4 INTERNAL PRESSURE
RELIEF OPEN
STRIP HEATERS
NOT OPERATING
OUTDOOR
THERMOSTAT
DEFECTIVE
ODT SETTING
TOO LOW
CAP TUBE PINCHED
OR BULB NOT
SENSING TRUE ODT
STRIP HEATER RELAY
OR CONTACTOR
DEFECTIVE
OPENING IN POWER
CIRCUIT TO HEATER
ELEMENTS
BLOWN FUSE LINK
BROKEN HEATER
ELEMENT
OPEN (KLIXON)
OVER-TEMPERATURE
THERMOSTAT
DEFECTIVE ROOM
THERMOSTAT
(2ND STAGE)