Scotsman MCM1462 Service Manual page 21

SERVICE DIAGNOSIS: Refrigeration and/or Mechanical
SYMPTOM
Poor harvest
Unit cycles off during freeze or
harvest
Low capacity
Unit runs out of water
Unit shuts off before bin is full
Unit does not shut off
POSSIBLE CAUSE
Too short harvest time
Restriction of incoming water
Hot gas valve does not open
Not enough refrigerant
Cube size too small
Hi temperature switch opens and
closes
Loose connection on PC board
High head pressure, from dirty
condenser, faulty fan motor, or fan
control
Non condensable gas in the system
Poor air circulation or extreme hot
location
Overcharge of refrigerant
Cube size too big, unit runs out of
water before harvest
Inlet water valve leaks thru
Hot gas valve leaks thru
Reservoir leaks
Inlet water valve restricted
Short harvest cycle
Water pressure too low
Something blocking transducer
Transducer is wet
Control not set on full
Ice level control failiure
Timer stuck; does not turn
April, 1993
Page 21
MCM1462
PROBABLE FIX
Check and adjust harvest time
Check supply, filter, strainer and valve
Check for power to the coil, check for
not opening, replace
Locate leak, repair, replace drier,
evacuate and weigh in nameplate
charge.
Adjust with cube size control
Hot gas valve leaks thru, replace it
Check and replace P C board
Clean condenser, repair fan motor or
control
Purge system, evacuate and weigh in
nameplate charge
Relocate the cabinet; or provide
ventilation
Evacuate and weigh in nameplate
charge
Adjust cube size control
Replace valve
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
Repair leak
Clean or replace valve
Adjust timer
Check supply
Remove blockage
Remove transducerand shake screen
dry.
Set control to full.
Check circuit, see next page.
Replace timer