Diagnostic Charts; No Ice Production - Hoshizaki KMD-850MAH Service Manual

5) Freeze Cycle – LED 1 is on. Compressor (and fan motor on a remote air-cooled
unit) remains energized, pump motor, (liquid line valve if applicable), and fan motor
(self-contained air-cooled unit) energize. The inlet water valve and hot gas valve de-
energize. The unit is held in freeze by a 5 minute short cycle protection timer. After
the 5 minute short cycle protection timer terminates, the freeze cycle operation is
transferred to the float switch for freeze termination. During the first 5 minutes of freeze,
confirm that the evaporator temperature drops. After 5 minutes in freeze, remove the
black float switch lead from the K5 connector. The unit should switch out of the freeze
cycle. Diagnosis: If the evaporator is not cold, check to see if the hot gas valve is still
open or if the expansion valve is not opening properly, if the water valve is continuing
to fill the reservoir, if there are improper unit pressures, an inoperative compressor, or
an inoperative headmaster (C.P.R.) (remote condenser unit only). If the unit remains in
freeze with the float switch removed, replace the board.
Note: Normal freeze cycle will last 20 to 40 minutes depending on model and
conditions. Cycle times and pressures should follow performance data provided
in this manual.
6) Pump-Out Cycle (10 second pump out) – LEDs 1, 4, 3, 2 are on. With S4 dip switch 5
and 6 in the factory default position, the 1st pump out occurs after the 11th freeze cycle
and every 10th cycle thereafter. The pump out cycle can be adjusted to occur every
cycle, or every 2, 5, or 10 cycles (S4 dip switch 5 & 6).
The compressor remains energized, the hot gas valve energizes, the fan motor
de-energizes (self-contained air-cooled unit only), the pump motor stops for 2 seconds.
The service relay energizes, opening the drain valve and water valve and restarting the
pump motor. Water is taken from the sump and pumped through the drain valve and
down the drain for 10 seconds. This removes contaminants from the water reservoir.
Diagnosis: If the pump motor does not run, check the circuit, service relay, and
capacitor. Check for proper voltage. If water does not pump out, make sure S4 dip
switch 3 & 4 are in the factory default positions, check and clean the tubing at the drain
valve, then check and clean the valve assembly.
7) Normal Harvest Cycle – same as the initial harvest cycle – Return to step 4.
Note: Unit continues to cycle until bin control is satisfied or power is switched off. The
unit always restarts at the 1 minute fill cycle.
B. Diagnostic Charts

1. No Ice Production

Problem
[1] The icemaker will not
start.
Possible Cause
a) Power Supply
b) Water Supply
c) Fuse (Control Box)
1. Off, blown fuse, or
tripped breaker.
2. Loose connection.
3. Bad contacts.
4. Not within
specifications.
1. Water supply off or
pressure too low.
1. Blown.
37
Remedy
1. Turn on, replace, or reset.
2. Tighten.
3. Check for continuity and
replace.
4. Refer to nameplate and
correct.
1. Check and get
recommended pressure.
1. Check for short circuit and
replace.