Manitowoc S0850M, Service Manual

Page: 51 / 100

Section 6 Electrical System
Part Number 80-1558-3
6-13
Symptoms
Bin Switch Fails Open
• The ice machine will not start with the toggle switch
in the ice position, but runs normally with the toggle
switch in the clean position.
Bin Switch Fails Closed
• Safety limit 2 is recorded in the control board
memory and the harvest cycle continues after the ice
opens and closes the water curtain (harvest cycle is
3.5 minutes long).
Diagnostic Aids:
• Always use the water curtain magnet to cycle the
switch (a larger or smaller magnet will affect switch
operation).
• Readings are affected by your test lead connection
and VOM battery strength. Verify you have solid
connections and a correctly functioning VOM before
testing bin switch.
• Open the curtain for 3 seconds, then close the
curtain for 3 seconds. This will allow your VOM
display to settle.
• With the bin switch closed your meter reading should
be 0 (0 to 10 is acceptable). With the curtain open the
reading must be infinity (OL).
Continuity Test
1. Disconnect the bin switch wires to isolate the bin
switch from the control board.
2. Connect an ohmmeter to the disconnected bin
switch wires.
3. Cycle the bin switch open and closed 25 times by
opening and closing the water curtain. Watch for
consistent readings each time the bin switch is
cycled open and closed (bin switch failure could be
erratic).
Water Curtain Removal Notes
The water curtain must be on (bin switch closed) to start
ice making. While a freeze cycle is in progress, the water
curtain can be removed and installed at any time without
interfering with the electrical control sequence.
If the ice machine goes into harvest sequence while the
water curtain is removed, one of the following will
happen:
• Water curtain remains off:
When the harvest cycle time reaches 3.5 minutes
and the bin switch is not closed, the ice machine
stops as though the bin were full.
• Water curtain is put back on:
If the bin switch closes prior to reaching the 3.5-
minute point, the ice machine immediately returns to
another freeze sequence prechill.