Scotsman MCM1462R - Manual (Page 24)

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 Adjust or replace TXV
MCM1462R
April, 1993
Page 24