Hoshizaki KM-250BWF Service Manual page 19

After the 1 minute ± 5 second water supply cycle and the 2 minute ± 10 second defrost
cycle, the unit should start the freeze cycle.
(ii) After the above step (i), disconnect the float switch leads 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.
Reconnect a 1.5 kΩ - 3.5 kΩ 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 by using test program of the controller board.
(i) Disconnect the connector K1 from the controller board. Set the dip switch No. 7 and 8
on the controller board to the "ON" position, and energize the unit.
(ii) The current flows to each relay (from X1 to X4) one after another every time the float
is raised and the contacts close. See the following chart, and check "OPEN" and
"CLOSE" of pins of the connector K1 at each step.
(iii) If the checks are completed, turn off the icemaker, plug the connector K1 into the
controller board as before, and set the dip switch No. 7 & 8 to the "OFF" position.
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