JOHNSON CONTROLS
23
FORM 160.76-O1
ISSUE DATE: 6/15/2015
5
SECTION 5 - TROUBLESHOOTING
TABLE 1 -
OPERATION ANALYSIS CHART
RESULTS
POSSIBLE CAUSE
REMEDY
1. SYMPTOM: ABNORMALLY HIGH DISCHARGE PRESSURE
Temperature difference between
condensing temperature and water off
condenser higher than normal.
Air in condenser.
High discharge pressure.
Condenser tubes dirty or scaled.
Clean condenser tubes. Check water
conditioning.
High condenser water temperature.
Reduce condenser water inlet
temperature. (Check cooling tower and
water circulation.)
Temperature difference between
condenser water on and water off
higher than normal, with normal
evaporator pressure.
Insufficient condensing water flow.
Increase the quantity of water through
the condenser to proper value.
2. SYMPTOM: ABNORMALLY LOW SUCTION PRESSURE
Temperature difference between
leaving chilled water and refrigerant in
evaporator greater than normal with
high discharge temperature.
Insufficient charge of refrigerant.
Check for leaks and charge refrigerant
into system.
Variable orifice problem.
Remove obstruction.
Temperature difference between leaving
chilled water and refrigerant in the
evaporator greater than normal with
normal discharge temperature.
Evaporator tubes dirty or restricted.
Clean evaporator tubes.
Temperature of chilled water too low
with with low motor amperes.
Insufficient load for system capacity.
Check prerotation vane motor operation
and setting of low water temperature
cutout.
3. SYMPTOM: HIGH EVAPORATOR PRESSURE
High chilled water temperature.
Prerotation vanes fail to open.
Check the prerotation vane motor
positioning circuit.
System overload.
Be sure the vanes are wide open
(without overloading the motor) until the
load decreases.
4. SYMPTOM: NO OIL PRESSURE WHEN SYSTEM START BUTTON PUSHED
Low oil pressure displayed on control
center; compressor will not start.
Oil pump running in wrong direction.
Check rotation of oil pump (Electrical
Connections).
Oil pump not running.
Troubleshoot electrical problem with oil
pump VSD.
5. SYMPTOM: UNUSUALLY HIGH OIL PRESSURE DEVELOPS WHEN OIL PUMP RUNS
Unusually high oil pressure is
displayed when the oil pressure
display key is pressed when the oil
pump is running.
High oil pressure. Transducer
defective.
Replace low or high oil pressure
transducer.
