Trane PolyTherm ARTC-SVX005A-EN - Page 65

Chiller/Heater Troubleshooting
ARTC-SVX005A-EN 65
Low water flow Increase flow rate
Condensing temperature too low Check source water modulation valve and temperature
Low water temperature Raise set point and increase flow; check design specification
Low discharge pressure Check for refrigerant leak
Expansion valve malfunctioning
Increase suction pressure; suction temperature pressure; check for
proper superheat; check electronic expansion valve replace if necessary;
cabling to stepping motor; contact Trane technical support
Compressor service valves closed Open service valve (if so equipped) counterclockwise completely
Clogged liquid line filter-drier Replace liquid line filter-drier or core
Excessive glycol concentration Drain, refill (deionized water), retest
Liquid line solenoid restricted or faulty Replace solenoid valve coil
Insufficient chilled water flow Adjust flow rate across evaporator
Restricted water/glycol line Clean strainers; check manual and electronic expansion valves
Water/glycol mixture contaminated
Intensive cleanup effort needed to identify source of contamination;
external filter may be required
Evaporator clogged or fouled
Reverse flush with appropriate chemical solutions following approved
procedures
7. Symptom: High refrigeration suction pressure
Possible Causes Potential Solutions
Expansion valve opened too far closed Re-adjust to 10° C to 12° C
Excessive refrigerant charge
Creates high pressure alarms; recover excess refrigerant; weigh in
correct charge as indicated on data plate
Entering water temperature excessive Failing tandem compressors; check design specifications
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
6. Symptom: Low refrigeration suction pressure (continued)
Possible Causes Potential Solutions