Welbilt Koolaire KD0270A, Technician'S Handbook, Page: 99 / 136

Part Number STH047 Rev01 10/18 99
Ice Thickness Probe
How the Probe Works
The Koolaire® electronic sensing circuit does not rely on
refrigerant pressure, evaporator temperature, water levels
or timers to produce consistent ice formation.
As ice forms on the evaporator, water (not ice) contacts the
ice thickness probe. After the water completes this circuit
across the probe continuously for 6-10 seconds, a harvest
cycle is initiated.
Freeze Time Lock-In Feature
The ice machine control system incorporates a freeze time
lock-in feature. This prevents the ice machine from short
cycling in and out of harvest.
The control board locks the ice machine in the freeze
cycle for six minutes. If water contacts the ice thickness
probe during these six minutes, the harvest light will come
on (to indicate that water is in contact with the probe),
but the ice machine will stay in the freeze cycle. After
the six minutes are up, a harvest cycle is initiated. This
is important to remember when performing diagnostic
procedures on the ice thickness control circuitry.
To allow the service technician to initiate a harvest cycle
without delay, this feature is not used on the first cycle
after moving the toggle switch OFF and back to ON.
Maximum Freeze Time
The control system includes a built-in safety, which will
automatically cycle the ice machine into harvest after
60 minutes in the freeze cycle.