4 Troubleshooting
Analysis and countermeasure of abnormalities
SMGB0120 rev.0 - 11/2017
126
Phenomenon
Cause
Check Item
Action · Countermeasure
The machine
is working, but
the heating
effect is poor.
Load bigger than heating capacity.
Conduct heating load
calculation
Set the machine to a larger
capacity
Suction
pressure is
too low.
(Low
pressure
interruption
control
activated)
Gas leakage or insufficient
amount of refrigerant
Check super heat
Charge correct refrigerant
volume after checking gas
leakage
Clogging of expansion valve
Check for clogging
Remove clogging
Malfunction of expansion
valve
Check operation of expansion
valve
Replace expansion valve
Clogging of suction pipes
Check whether there is
temperature difference in the
pipes
Remove clogging.
Suction
pressure is
too low. (Low
pressure
interruption
control
activated)
Malfunction of check valve
There is temperature
difference before and after
check valve.
Replace check valve
Discharge
pressure too
high.
(High
pressure
switch
activation)
Insufficient volume of water
Check cold water inlet/outlet
temperature difference
Increase volume of water
Pump inverse rotation
Check rotational direction
Fix to correct direction
Air mixture
Try to open ventilator valve
Ventilator
Hot water temperature too
high
Check activation of the hot
water thermostat
Replace thermostat
Refrigerant overcharge
Check cycle temperature
Charge correct volume
Mixture of non-condensable
gas in refrigerant cycle
Stop the chiller unit and check
the relation between water
temperature and pressure
Recharge refrigerant after
vacuum pumping
Clogging of pipes at
discharge side
Check for clogging
Remove clogging.
Clogging of expansion valve
Check for clogging
Malfunction of expansion
valve
Check operation of expansion
valve
Replace expansion valve
Formation of lime deposit
inside water-side heat
exchanger
Check for dirt inside water-side
heat exchanger
Clean water-side heat exchanger
Malfunction of check valve
Check temperature difference
before and after check valve
Replace check valve
The machine
is working, but
it produces
abnormal
noises
Sounds come
from the
compressor
Incorrect installation or
loosening of various
tightening bolts
Inspection of loosening of
each tightening bolt
Tighten bolts even more
Liquid compression
Check temperature and
pressure of suction gas
Secure super heat
Oil hammer
Check temperature and
amount of oil in suction gas
Check or replace compressor
Oil heater is not being
supplied power during stop
Check the power supply to the
oil heater
Replace oil heater
Exhaustion and damage
inside the compressor
Abnormal noises produced
inside the compressor
Compressor replacement
Howling from the electrical contactor
Check for rough contact
Replace contact
Vibration of cabinet
Check for loosening of screws
Retighten screws