TENNEY ENVIRONMENTAL
Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4
Page 45
TENNEY JUNIOR TROUBLESHOOTING GUIDE - continued
PROBLEM POSSIBLE CAUSE CORRECTIVE ACTION
8. Compressor starts, hums, runs
slowly, staying on start winding
Low line voltage Get proper electrical service
Compressor relay is stuck Replace
Shorted winding Test resistances, test for grounds,
contact Tenney Service
9. Low stage compressor will not
run
Pressure switch PS2 not closing Contact Tenney Service
10. Low stage runs, but little or no
cooling
Low stage is low on refrigerant Have system leak tested
Artificial loading valve SV stuck open
full time
Replace
Main cooling coil badly frosted Raise temperature to defrost
11. Compressor runs but cools
inefficiently
Restricted ventilation, dirty condenser
fins
Move unit away from wall, clean
condenser fins
12. Refrigeration works long or
continuously
Excessive heat load Reduce load if possible
Ice on evaporator coil Defrost
Low refrigerant charge Have charge checked by refrigeration
mechanic - charges are on ID label
13. Compressor repeatedly trips
out overload protector
Pressure switch failure Have refrigeration mechanic check
switches. Contact Tenney Service
14. Noisy compressors
Compressor loose on mounts Tighten hold down nuts
15. Noisy compressors, even with
secure hold-downs
Broken springs within compressor
housing
Replace compressor - Call Tenney for
assistance
NOTE: At site ambient temperature, if the chamber does not pull down substantially in
temperature within 15 minutes, something is wrong. Turn the chamber off. Let it normalize and defrost.
Then, try it again. If it still does not pull down to low temperature, shut it off and get technical help. A
refrigeration system which does not cool properly should not be run for prolonged periods. It may have a
leak and be low on refrigerant. Since the compressor depends upon cool returning refrigerant for cooling, it
can be overheated when operated in an undercharged system.
Remember that the compressors have internal overloads with automatic reset; these are in addition to circuit
breakers. Therefore, when a compressor cuts out, it must be given time to cool so that its internal protector
has time to reset.
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