Evaporator Is Frozen Up - Hoshizaki KM-251BAH Service Manual

Problem
[7] All components
run, but no ice is
produced.

2. Evaporator is Frozen Up

Problem
[1]Freeze cycle time is
too long.
[2]All ice formed on
evaporator does not
fall into bin in harvest
cycle.
[3]Other
Possible Cause
b) Control Board
a) Refrigerant
b) Compressor
c) Hot Gas Valve
d) Harvest Water Valve
e) Water Valve Relay
Possible Cause
a) Float Switch
b) Water Valves
c) Control Board
a) Evaporator
b) Water Supply Line
c) Water Filter System
d) Water Valves
e) Ambient and/or water
temperature.
f) Thermistor
g) Control Board
a) Spray Tubes
b) Water System
1. Defective.
1. Undercharged.
2. Air or moisture
trapped.
1. Defective valve.
1. Continues to open in
freeze cycle.
1. Water valve is wide
open during freeze.
1. Contacts stuck.
1. Leads shorted or
defective switch.
2. Float does not move
freely.
1. Diaphragm does not
close.
1. Defective.
1. Scaled up.
1. Water pressure too
low.
1. Dirty/Restricted
1. Dirty mesh filter or
orifice.
2. Diaphragm does not
close.
1. Too cool.
1. Out of position or
loose attachment.
1. Harvest timer is set
too short.
2. Defective.
1. Clogged.
2. Out of position.
1. Dirty.
26
Remedy
1. See "II.C.6. Control Board
Check Procedure."
1. Check for leaks and
recharge.
2. Replace drier and
recharge.
1. Replace.
1. Check and replace.
1. Check for water leaks with
icemaker off.
1. Replace.
Remedy
1. Check and replace.
2. Clean or replace.
1. Check for water leaks with
icemaker off.
1. See "II.C.6. Control Board
Check Procedure."
1. Clean.
1. Check and get
recommended pressure.
1. Replace filter.
1. Clean.
2. Check for water leaks with
icemaker off.
1. Increase temperature.
1. See "V.I. Removal
and Replacement of
Thermistor."
1. Adjust longer, referring
to "II.C.3. Controls and
Adjustments, c) Harvest
Timer.
2. See "II.C.6. Control Board
Check Procedure."
1. Clean
2. Place in position.
1. Clean.