Johnson Controls YEWS Series, Installation, Operation And Maintanance Instructions

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Cooling water temperature too low
Jet or orifice of oil eductor clogged
Insufficient oil charge
Overcharged oil
Cooling water temperature too high
Condenser tubes dirty or scaled
Insufficient condenser water flow
Faulty compressor discharge valve
Faulty discharge pressure sensor
Air in condenser
Cooling water temperature too low
Faulty oil pressure or evaporation
pressure sensor
Oil filter(inside the compressor)
clogged
Faulty discharge pressure or oil
pressure sensor
Cooling water temperature too high
Condenser tubes dirty or scaled
Insufficient load for system capacity
Over charged with refrigerant
Refrigerant saturated with oil
Over charged with oil
Slide valve fail to unload
Wrong value of LOW LELT
Compressor load too speedy
Wrong value of CUR.OFFSET
Low discharge superheat with low leaving
cooling water temperature
No notable temperature difference on the oil
eductor
Oil level is low while the chiller operating in
nomal condition
High oil level with evaporator foaming
High condenser water temperature
Temperature difference between refrigerant and
water off of condenser greater than normal
Temperature difference between condesner
water on and water off higher than nomal,with
nomal evaporator pressure
High discharge pressure or the High discharge
pressure switch tripped
Abnormal discharge pressure observed in the
panel
Temperature difference between liquid
refrigerant temperature and water off condenser
higher than normal
Pressure difference between oil pressure and
discharge pressure too small
Abnormal oil or discharge pressure observed in
the panel
Pressure difference between oil pressure and
discharge pressure greater than 200 kPa
Abnormal oil or discharge pressure observed in
the panel
High condenser water temperature
Temperature difference between liquid
refrigerant temperature and water off condenser
higher than normal
High discharge superheat with low motor
amperes
Low discharge superheat with foaming in oil
separator
Evaporator foaming and low discharge
superheat
High oil level with evaporator foaming
Motor current greater than normal when the
chiller stop
“
LOW LELT
”
set falling within chiller
cycling region
Unloading time set too big
Current showed in panel greater than the lab test
Increase condenser water temperature
Change oil filter and oil eductor
Charge oil into compressor
Recover some oil from compressor
Reduce condenser water inlet temperat-
ure.(Check cooling tower and water cir-
culation)
Clean condenser tubes.Check water
conditioning
Increase the quantity of water through
the condenser to proper value
Check the compressor discharge valve
Change pressure sensor
Purge unit
Increase condenser water temperature
Change pressure sensor
Change oil filter
Change pressure sensor
R e d u c e c o n d e n s e r w a t e r i n l e t
temperature.(Check cooling towen and
water circulation)
Clean condenser tubes
Increase compressor min operation
current set
Adjust charge
Perform oil recovery and check oil levels
Adjust oil charge
"Check compressor slide valve and slide
valve solenoid valve;Set the compressor
unloading time to proper value"
Adjust water temperature set value
Adjust compressor loading time set
Adjust current offset to proper value
4. Symptom: Insufficient oil supply pressure
5. Symptom: The difference of discharge pressure and oil pressure is too high
6. Symptom: High discharge temperature
7. Symptom: Low discharge superheat
8.Symptom: Low chilled water temperature
9. Symptom: Motor over current
3.Symptom: High discharge pressure
YEWS-E Water Cooling Screw Chiller/Heat Pump
63