SERVICE DIAGNOSIS: Refrigeration and/or Mechanical
SYMPTOM
POSSIBLE CAUSE
PROBABLE FIX
Poor harvest
Hot gas valve does not open
Check for power to the coil, check
for not opening, replace
Head pressure control valve does
not maintain enough head
pressure.
Replace head pressure control
valve.
Unit cycles off during freeze or
harvest
Hi temperature switch opens and
closes
Hot gas valve leaks thru, replace it
Low capacity
High head pressure, from dirty
condenser, faulty fan motor
Clean condenser, repair fan
motor
Non condensable gas in the
system
Purge system, evacuate and
weigh in nameplate charge
Extreme hot location
Relocate the cabinet
Overcharge of refrigerant
Evacuate and weigh in nameplate
charge
Hot gas valve leaks thru
At the end of the freeze cycle
there should be frost on the
evaporator end of the hot gas
tubes, if not replace the hot gas
valve
Liquid and discharge lines are in
contact with each other
Separate and insulate them
Unit shuts off before bin is full
Bin Ice level control is set to
“Partial”
Move bin Ice level rocker switch
to “Full”.
Compressor cycles on and off
Low pressure control opening
and closing
Check low side pressure, liquid
line valve must open and low side
pressure raise over 35 PSIG
before pump down control will
close to run compressor
Compressor overheats
TXV not letting enough refrigerant
into evaporators, adjust or
replace TXV
Mechanical fault with
compressor, replace compressor
Frost on compressor
Some frost will not hurt
Do nothing
TXV meters too much refrigerant
Replace TXV
CME1202R & CME1402R
June 1996
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