Troubleshooting
FAULT
CAUSE
REMEDY
A
Discharge pressure too
high
1. Discharge stop valve not fully
open
Open fully
2. Discharge pressure gauge
defective
Repair or replace
3. Non-condensables in the system
Purge with a Automatic Purger
B
Discharge temperature too
high
1. Discharge pressure too high
See A
2. Too many cylinders cut out
Cut in more cylinders
3. Suction pressure too low
See D
4. Excessive superheat of suction
gas
Eliminate excessive superheat
5. Room temperature too high
Ventilate engine room better
6. Discharge valve defective
Repair or renew
7. Pressure relief valve is leaking
Repair or renew
C
Suction pressure too high
1. Capacity control does not
operate
Repair
2. Compressor capacity too small
Refer to plant design
3. Suction pressure gauge defective Repair or renew
4. One or more suction valves
defective
Renew suction valve rings
5. One or more discharge valves
defective
Repair or renew
6. Pressure relief valve is leaking
Repair or renew
D
Suction pressure too low
1. Suction stop valve not fully open
Open fully
2. Suction gas strainer blocked
Renew
3. Injection control not adjusted
correctly
Re-adjust control
4. Too little refrigerant in installation
Top-up with refrigerant
5. Suction pressure gauge defective Renew
E
Crankcase frosted or wet
*
6
Warning!
Stop compressor and contact installation engineer
1. Liquid refrigerant in crankcase
due to:
1a. Room temperature too low
Provide for crankcase heating or, if
provided, check it for proper operation
1b. Oil return from separator
contains liquid refrigerant
Consult plant manual
1c. Installation operates wet
Re-adjust installation and provide for
superheat
1d. Liquid separator too small
Consult plant manual
F
All cylinders inactive while
compressor is operating
1. Oil pressure for valve lifting
mechanism too low
See J
2. Incorrect wiring of capacity
control
Refer to the "Product Information”
6
In case of R744 applications only, crankcase can be frosted or wet, during normal operating conditions.
INSPECTION AND TROUBLE SHOOTING
TROUBLESHOOTING TABLE GRASSO RECIPROCATING COMPRESSORS
P-NL-094_imm_VHS_English_13
26.07.2021
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