Evaporator Is Frozen Up - Hoshizaki KM-901MAH Service Manual

Problem
[7] Fan motor will
not start, or is not
operating (except
water-cooled model).
[8] All components
run, but no ice is
produced.

2. Evaporator is Frozen Up

Problem
[1]Freeze cycle time is
too long.
Possible Cause
a) Fan Motor
b) Control Board
a) Refrigerant
b) Compressor
c) Hot Gas Valve
d) Liquid Line Valve
(if applicable)
e) Inlet Water Valve
f) Expansion Valve
g) Headmaster (C.P.R.)
(remote condenser
unit)
h) Water Supply Line
(water-cooled model)
i) Water Regulating Valve
(water-cooled model)
Possible Cause
a) Inlet Water Valve
b) Float Switch
c) Evaporator
d) Spray Tubes
e) Pump Motor
1. Motor winding open.
2. Bearing worn out.
3. Wiring to fan motor.
4. Defective capacitor.
5. Fan blade bound.
1. Defective.
1. Low charge.
2. Air or moisture
trapped.
1. Defective.
1. Continues to open in
freeze cycle.
1. Continues to close in
freeze cycle.
1. Inlet water valve is
wide open during
freeze.
1. Bulb loose.
2. Operating erratically.
1. Not operating properly
and liquid line
temperature too warm.
1. Condenser water
pressure too low or
off and high pressure
control opens and
closes frequently.
1. Set too high.
1. Diaphragm does not
close.
1. Float does not move
freely or defective
switch.
1. Scaled up.
2. Damaged.
1. Dirty.
2. Out of position.
1. RPM too slow.
63
Remedy
1. Replace.
2. Replace.
3. Check for loose connection
or open, and replace.
4. Replace.
5. Check and replace.
1. See "IV.B. Control Board
Check."
1. Check for leaks. Recover,
repair, evacuate, and
recharge.
2. Recover, replace drier,
evacuate, and recharge.
1. Replace.
1. Check and replace.
1. Check and replace.
1. Check for water leaks with
icemaker off.
1. Secure bulb.
2. Check and replace.
1. Replace headmaster.
1. Check and get
recommended pressure.
1. Adjust or replace. See
"V.J. Adjustment of Water
Regulating Valve."
Remedy
1. Check for water leaks with
icemaker off.
1. Clean or replace. See "IV.
D. Float Switch Check and
Cleaning."
1. Clean.
2. Replace.
1. Clean.
2. Place in position.
1. See chart 1.[5].