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