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C C h h i i l l l l e e r r / / H H e e a a t t e e r r T T r r o o u u b b l l e e s s h h o o o o t t i i n n g g
8. Symptom: Low refrigerant discharge pressure
Possible Causes
Suction shut off valve partially closed
Insufficient refrigerant in chiller/heater
Low suction pressure
Source heat exchanger modulating valve not properly adjusted or not
functioning
9. Symptom: High refrigerant discharge pressure
Possible Causes
System overcharged with refrigerant
Non-condensables in chiller/heater
Restricted bypass line
Discharge shut off valve partially closed
Liquid line solenoid valve coil
10. Symptom: Low chilled water temperature
Possible Causes
Temperature set point set adjusted too low
Water flow rate through evaporator too low
System controls malfunctioning
11. Symptom: High chilled water temperature
Possible Causes
Refrigeration circuits not cooling
Load higher than capacity of chiller/heater
Low refrigeration charge
Load higher than capacity of chiller/heater
Low refrigeration charge
Temperature sensor not properly installed
Fouled evaporator
Excessive flow through evaporator
12. Symptom: Compressor thermal protector switch open (overloading)
Possible Causes
Electrical malfunction
Operating beyond design conditions
Discharge valve partially shut
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Potential Solutions
Open valve
Check for leaks. Repair and add R410A or R134A as needed
See low pressure below
Refer to OEM manufacturer manual for default settings; check Y1
electrical output J6
Potential Solutions
Remove excess refrigerant
Purge non-condensables according to approved procedures
Check valves obstructed; flush line; blow out line with dry nitrogen
gas
Open valve
Check valve; replace if defective
Potential Solutions
Reset temperature set point to correct design specifications (low
return temperatures)
Clean strainer; check pump, and differential pressure settings
Check and replace temperature sensors if necessary
Potential Solutions
Check electronic expansion valve for excessive flow; adjust or replace
electronic expansion valve
Refer to chiller/heater design specifications
Conduct leak check on refrigeration system
Refer to chiller/heater design specifications
Conduct leak check on refrigeration system
Check that sensor is properly installed in well
Reverse flush evaporator; check strainer for debris
Reverse flush evaporator; check strainer for debris; check pump,
valves
Potential Solutions
Check contactors for damage; check wiring for loose connections;
replace compressors
Allocate chiller/heater for use within operating capacity. Add
equipment
Open valve
ARTC-SVX005B-EN
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