Scotsman C2648 - SERVICE MANUAL 11-2010 Service Manual page 43

C2648 Service Manual
Diagnostics - Remote Air Cooled
Problem
Shut Down on Maximum
Freeze Time (continued)
Shut down on maximum
harvest time
Likely Cause
Compressor not operating
(continued)
Low refrigerant charge
Hot gas valve leaks through
during freeze
Thermostatic expansion valve
bulb loose
Thermostatic expansion valve
producing very low or very high
superheat
Compressor inefficient
Debris in refrigeration system
Ice bridge thickness too small, not
enough ice to open curtain
Ice bridge thickness too large, ice
frozen to evaporator frame
Purge valve does not open, water
melts ice bridge, not enough ice to
open curtain
Incomplete ice formation
Curtain out of position
November 2010
Page 20
Probable Solution
Check compressor temperature
Check compressor voltage
Check compressor windings
Add some refrigerant and restart
unit. If cycle time improves, look
for leak.
Check hot gas valve for hot outlet
during freeze
Check bulb
Check evaporator superheat,
change TXV if incorrect
Check compressor amp draw, if
low and all else is correct, change
compressor
Recover charge. Open quick
connects, check for loose or
missing foil. Open liquid line and
hot gas valves. Check for debris.
Replace drier, evacuate and
weigh in nameplate charge.
Check and adjust if needed
Check and adjust if needed
Check purge valve
Check water distributor for
partially plugged holes
Check curtain for swing restriction