Hoshizaki KM-280MAH-E, Service Manual

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(ii) After the above step (i), disconnect the float switch leads (K5) from the controller board
within the first 5 minutes of the freeze cycle.
The unit should go into the defrost cycle after the first 5 minutes ± 20 seconds of the
freeze cycle.
(iii) Reconnect the float switch connector to the controller board. After the first 5 minutes of
the freeze cycle, disconnect the float switch leads from the controller board.
At this point, the unit should start the defrost cycle.
(iv) After step (iii), de-energize the unit and confirm that the defrost timer is in the minimum
position. Disconnect the resistor from the controller board, and energize the unit.
After the 1 minute water supply cycle, the defrost cycle starts.
Re-connect a 1.5 k
Ω
- 3.5 k
Ω
resistor to the connector K3 (pins #1 and #2) after the first
2 minutes of the defrost cycle. The unit should start the freeze cycle after 1 minute ± 5
seconds from the resistor connection.
3) Check the controller board using the controller board’s test program.
The output test switch “S3” provides a relay sequence test. With power OFF, place S3 on
and switch power to ICE. The correct lighting sequence should be none, 2, 3, 4, 1, and 4,
normal sequence every 5 seconds. S3 should remain in the “OFF” position for normal
operation.
D. Mechanical Bin Control
(These instructions are not applicable to models with thermostat.)
1. Proximity Switch
This machine uses a lever-actuated proximity switch (hereafter called “mechanical bin
control”) to control the ice level in the storage bin.
2. Explanation of Operation
a) The startup and shutdown of the ice machine is controlled via the controller board. Dip
switch number 7 must be in the ON position for the controller board to receive input from
the bin control.
(1) The controller board receives a resistance value input via the red K4 connector
from the bin control. A resistor wire harness is connected from the bin control to
the controller board.
(2) When the bin control is activated in the bin full position (pushed to the right), a
15.8 K
Ω
signal will be sent to the control board to shut down the unit.
(3) When the bin control is in the normal position (bin is not full), a 7.9 K
Ω
reading is
sent to the control board to continue operation.