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C. Compressor shortcycles
Problems and symptoms
Suction pressure too low and
frosting at driver.
Motor starts and stops frequently
Probable cause
Restricted liquid liner driver.
Faulty motor.
Recommended action
Replace driver core.
Replace compressor.
D. Compressor runs Continuously
Problems and symptoms
High temperature in conditioned
space
Bubbles in sight glass
Probable cause
Excessively high cooling load
a) Lack of refrigerant.
b) Filter driver obstructed
Recommended action
Check infiltration and insulation
of conditioned space.
a) Repair leak, add refrigerant.
b) Replace driver core.
E. Compressor loses oil
Problems and symptoms
Oil level too low (sight glass).
Gradual drop of oil level.
Excessively cold suction.
Noisy compressor
Probable cause
Insufficient oil charge.
Clogged filter drier
Liquid flooding back to compressor
Recommended action
All oil.
Replace.
Readjust superheat setting
and verify correct bulb
mounting.
F. Compressor is noisy
Problems and symptoms
Abnormally cold suction line:
compressor knocks. Valve bulb
attachment.
Compressor noisy
Probable cause
a) Liquid flood-back
b) Expansion Valve stuck in open
position
Incorrect direction of rotation
Recommended action
a) Check superheat and
expansion.
b) Repair or replace
Inverse the direction of rotation
G. System short of capacity
Problems and symptoms.
Expansion valve hissed.
High pressure drop across
filter-drier.
Superheat too high.
Superheat too high.
Probable cause.
Lack of refrigerant.
Clogged filter-driver.
Superheat set too high.
Excessive pressure drop in the
thermal expansion valve.
Recommended action
Add refrigerant.
Clean or replace.
Check superheat and adjust
expansion valve
Check superheat and reset thermal
expansion valve
Trouble Analysis
