41
Table 18: Service Analyzer Chart (cont.)
LOSS OF LUBRICATION
SYMPTOM POSSIBLE CAUSE REMEDY
Compressor failures Vapor line tubing too large Reduce tubing size to improve oil return.
Low suction pressure
Low charge Check system charge.
Refrigerant leaks Repair and recharge.
Cold, noisy
compressor –
Slugging
Dilution of oil with refrigerant Observe piping guidelines.
Noisy compressor Migration Check stater heat and compressor thermistor.
Cold, sweating
compressor
Flooding Check system charge.
Low load
Reduced airow
Dirty lter
Dirty coil
Wrong duct size
Restricted duct
Thermostat setting Advise customer.
Short cycling of
compressor
Cycling or faulty high or low pressure control
Check pressure and address cause of any abnormal
pressure. Replace control if faulty.
Loose wiring Check all control wires.
Thermostat
In supply air stream, out of calibration
Customer misuse
LIQUID REFRIGERANT SLUGGING
SYMPTOM POSSIBLE CAUSE REMEDY
On start-up Incorrect piping Review pipe size guidelines.
EXV hunting when
running
Faulty EXV components
Check EXV, suction pressure transducer, and suction
thermistor for operation.
REFRIGERANT FLOOD BACK
SYMPTOM POSSIBLE CAUSE REMEDY
Poor system control
using an EXV
Bad pressure reading Check transducer wiring.
Suction thermistor in wrong location Relocate thermistor.
Bad suction thermistor Replace thermistor.
Improper superheat setting (less than 5°F
[-2.8°C])
Adjust EXV SH setpoint dipswitches and validate
valve operation.
Diagnostics
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