Manitowoc b970 series, Technician'S Handbook

Page: 179 / 264

Part Number STH025 8/12 179
Diagnostics
ICE MACHINE CYCLES INTO HARVEST BEFORE
ICE CONTACTS THE ICE THICKNESS PROBE
Premature harvest symptoms
• Low ice production
• Thin ice in bin
• Freeze cycles are faster than published cycle
times
1. Turn off power and inspect ice thickness probe for
physical damage. Look for bulging, cracks around
the nipple or deformed pivot pins.
2. Verify ice thickness probe gap is approximately

9/32” (7 mm)
3. Make sure the ice thickness probe wire doesn’t
restrict movement.
4. Perform Ice Thickness Probe tap test:
• Press the menu button, scroll down to Service,
press the right arrow, scroll down to Real Time
Data, press right arrow - With the brackets around
Time & Temp press the right arrow - Scroll down
until 100Hz &120Hz are displayed. Slowly
increasing and decreasing numbers typically in the
200Hz to 300Hz range will display to the right of
100Hz &120Hz.
• Lift the Ice Thickness Probe and continuously tap
the nipple while watching the numbers to the right
of the 100Hz and 120Hz. There is a slight delay
while tapping.
Pass
Numbers increasing into the thousands indicates a
properly working ice thickness probe and control
board.
Fail
Numbers do not move or do not increase into the
thousands - Ohm the ice thickness probe.