11: Capacity Control Malfunction - mycom 1612LSC series Instruction Manual

10: Capacity control position is indicated incorrectly (continued)
Direct cause
Inaccurate reading of
capacity control indicator
on the control panel.

11: Capacity control malfunction

Direct cause
↑ See the causes for
"Inaccurate reading of
capacity control indicator
on the control panel".
"Micro-switches and
micro-switch cam" of the
indicator do not sense
"100%" position and/or
"0%" position.
Failure of capacity control
solenoid valve or related
relays
Internal leakage of
capacity control solenoid
valve
Defective capacity control
oil supply line
Unloader piston does not
move.
(Though this is one of the
causes of "Defective
capacity control oil supply
line", it is listed separately
here.)
Compound 2-stage Screw Compressor 1612LSC Speed Increaser Type
Root cause
E/E positioner or/and indicator
is faulty.
Loosened terminals or
defective wires
Root cause
Same as left
Micro-switch failure
Loosening of micro-switch or
micro-switch cam screw due to
vibration.
Mostly caused by coil burnout.
Oil compression due to
temperature rise inside
unloader cylinder
Improper adjustment of oil flow
control valve
Leak/clogging in solenoid valve
gland or oil supply piping
Damage on the cap seal of the
piston
Cap seal is pinched.
Cap seal is worn.
There is residual refrigerant
gas inside unloader cylinder.
6-8
2202L5JE-DA-C5-N_2015.05.
6 Troubleshooting
Action
If deteriorated over time, replace.
If there are specific causes such as
surge current, remove the cause or
take proper action.
Tighten the terminals if loosened.
Replace defective wires.
Action
Same as left
Replace.
Adjust the position of the cam and
switch, and tighten them.
Use thread locking agent when
necessary.
When compressor's vibration is
unusually high, see Item No. 12
"Compressor generates abnormal
vibration and/or sound".
If deteriorated over time, replace.
If the symptom is caused by wet with
water, etc., remove the cause(s) and
then replace defective part(s).
For details, refer to the instruction
manual of solenoid valve.
If the symptom is caused by long
duration of low-load operation, review
and improve the operating method.
Arrange inline check valve and oil
bypass route on the capacity control
oil supply line.
Readjust.
Remove cause, and check oil for
contamination/replace oil.
Check oil for contamination/replace
oil.
Replace O-ring, cap seal, etc.
Replace O-ring, cap seal, etc.
Check oil for contamination/replace
oil. Replace O-ring, cap seal, etc.
Stop the compressor. By operating the
oil pump, repeat load/unload
operation to purge refrigerant gas
from unloader cylinder.
In case of liquid flow-back, remove the
cause(s).
If oil heater or devices on its control
circuit are defective, replace the
defective part.