Manitowoc Marine Q 1800 Service Manual page 16

Electrical System
Check Procedure
1. Set the toggle switch to OFF.
2. Watch the bin switch light on the control board.
3. Move the water curtain toward the evaporator.
The bin switch must close. The bin switch light
"on" indicates the bin switch has closed
properly.
4. Move the water curtain away from the
evaporator. The bin switch must open. The bin
switch light "off" indicates the bin switch has
opened properly.
Ohm 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. Set the ohmmeter to the 10,000
ohm scale.
3. Cycle the bin switch by opening and closing the
water curtain.
4. With the bin switch open: Resistance readings
of more than 30,000 ohms indicate a correctly
operating bin switch.
5. With the bin switch closed: Resistance readings
of less than 70 ohms indicates a correctly
operating bin switch.
Important
Any reading between 70 and 30,000 ohms,
regardless of curtain position, indicates a
defective bin switch
70 OHMS
SWITCH CLOSED
0 OHMS
GOOD
Bin Switch Resistance Readings
12
INFINITE
30,000 OHMS
OHMS
SWITCH OPEN
METER
READS
(OL)
GOOD
BAD
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.