Hoshizaki KM-1900SAH Service Manual page 44

5) Freeze Cycle – LED 1 is on. Compressor (and fan motors on remote air-cooled
models) remains energized, pump motor, liquid line valve, (and self-contained fan
motors on air-cooled models) 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 inlet 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). 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 – LEDs 1, 4, 3, 2 are on. The 1st pump out occurs after the
1st freeze cycle and every 10th cycle thereafter (S4 dip switch 5 & 6). The pump out
cycle can be adjusted to occur every cycle, or every 2, 5, or 10 cycles (S4 dip switch
5 and 6).
The compressor remains energized, the hot gas valve energizes, the fan motors
de-energize (air-cooled models). The pump motor stops for 2 seconds. The pump
motor then re-starts in the reverse direction, taking water from the bottom of the sump
and forcing pressure against the check valve seat allowing water to go through the
check valve and down the drain. At the same time, water flows through the small tube
to power flush the float switch. Diagnosis: If the pump motor does not run, check the
circuit and pump capacitor. If the pump motor does not reverse and water does not
pump out, check S4 dip switches 3 and 4, check for clear tubing at the check valve
housing, and check the unit drain for water flow. Remove the pump out check valve
housing and check/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.
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