Carrier 50CR - Manual (Page 31)

31
Table 7—Troubleshooting Chart (Cont’d)
SYMPTOM CAUSE REMEDY
Head pressure too low
Low refrigerant charge Check for leaks, repair and recharge
Restriction in liquid tube Remove restriction
Excessive suction pressure
(Cool) High Heat load Check for source and eliminate
Reversing valve hung up or leaking internally Replace valve
Refrigerant overcharged Recover excess refrigerant
Suction pressure too low
(Cool) Dirty air filter Replace filter
(Heat) Outdoor coil frosted
Move timer on control board to 30 minutes between
defrost cycles
Low refrigerant charge Check for leaks, repair and recharge
Metering device or low side restricted Remove source of restriction
(Cool) Insufficient coil airflow
Increase air quantity
Check filter–replace if necessary
(Cool) Temperature too low in conditioned area Reset UI setting
(Cool) Outdoor ambient below 55°F Install low--ambient kit
Filter drier restricted Replace
Compressor runs but outdoor fan does not
NC (normally closed) contacts on defrost board
open
Check condition of relay on board
Replace if necessary
IFM does not run
Blower wheel not secured to shaft Properly tighten blower wheel to shaft
Insufficient voltage at motor Determine cause and correct
Power connectors not properly sealed Connectors should snap easily; do not force
IFM operation is intermittent
Water dripping into motor Verify proper drip loops in connector wires
Connectors not firmly sealed
Gently pull wires individually to be sure they are
crimped into the housing
IFM--Indoor Fan Motor
50C
R