SERVICE DIAGNOSIS: Condition - No Ice Being Produced
STATUS:
NOTHING OPERATES
A. Check: Voltage to the unit, restore it if there is none. Compare to the nameplate.
B. Check: The master switch, switch ON if off.
C. Check: The 2 reset switches (spout switch, or on prior models, the circuit board; and high
pressure): depress and release each switch. If the unit still does not start, check the spout switch,
or high side pressure.
D. Check the high pressure cut out switch, if closed, go to E; if open:
1. This pressure switch opens at 450 psig. Check the high side pressure, reset the switch and
observe that the fan is forcing air through the condenser. If the switch opens at pressures below
450 psig, replace the switch. If the pressures rise above the trip out point, and the unit shuts down:
a. Check for adequate air flow. Clean the condenser. If the air flow is poor because of the
installation, advise the user that the unit should be moved, or the air around it kept cooler.
Check the fan motor for tight bearings and proper rotation.
Check that the fan blades are clean, and the fan secure to the fan motor shaft.
b. Check the head pressure control valve, it should be maintaining a head pressure
above 220 psig. If the unit has the correct charge, and the condenser is clean, and the
refrigerant lines are not kinked or twisted, and the condenser is not overheated by
external heat loads, the head pressure should be under the trip out point of the head
pressure control switch. If all of the above are found to be good, and the machine
trips out on high head pressure, replace the head pressure control valve.
E. Check the spout switch.
1. This switch will open if the bin control (ice level sensor) does not shut the machine off when the
ice storage bin is full of ice: ice backs up in the ice chute, and internal pressure opens the switch,
stopping the machine. On units older than July, 1990 prodiuction, this switch will reset after the
ice melts, but the machine will not restart until the reset switch in the control box is pressed. If the
machine does start, check:
a. The ice level sensors, they may need cleaning (see maintenance).
b. The circuit board, see next page.
F. Check the water level. If there is not enough water in the reservoir, the water level sensor will
keep the machine from starting.
a. Check the water level, restore/adjust if low.
b. Check the water level sensor, clean if dirty, (see maintenance).
c. Check the circuit board, see next page.
If the machine does not start, see the next page.
NM1850R
September, 1992
Page 24
