14
7)
Refill/Low-Water Safety Cycle
–As ice is produced, water level in the reservoir drops.
UFS opens, nothing happens at this time. LFS opens and refill begins. X4 relay
de-energizes, low water safety circuit opens (X4 relay #4 (DBU) and #6 (BR), and
CB #3 (BR) and #4 (DBU)), CB 90 sec. low-water safety timer starts. WV energizes.
Comp, FM, GM, and X3 relay continue. UFS must close before 90 sec. low-water safety
timer terminates. Otherwise, shutdown cycle is initiated. Once UFS closes, X4 relay
energizes, WV de-energizes, and low-water safety circuit closes, terminating 90 sec.
low-water safety timer.
Diagnosis
– Check that WV energizes. If not, confirm LFS status (open), X4 relay
de-energized. If not, see step 5 above.
8)
Shutdown
–Ice fills ice storage bin and presses BC actuator to open BC. Comp, FM,
GM, and X3 relay continue. X5 relay and X4 relay de-energize. 90 sec. low-water
safety timer starts. When 90 sec. low-water safety timer terminates, Comp and FM
de-energize. GM and X3 relay continue. 60 sec. GM delay timer starts. Once 60 sec.
GM delay timer terminates, GM and X3 relay de-energize. DV energizes. Reservoir and
evaporator drain. DV remains energized until BC closes again.
Diagnosis:
Check that BC actuator paddle is activated and not sticking. Confirm BC
is open and X5 relay de-energizes. If not, see "II.D. Bin Control Check." Next, confirm
X4 relay de-energizes. If not, check for 24VAC at X5 relay #3 (R) to neutral (LBU).
If 24VAC is present, replace X5 relay. If X4 relay is de-energized, after 90 sec. confirm
Comp and FM de-energize. If not, check for 35VDC at CB #3 (BR) to CB #4 (DBU).
If 0VDC is present, replace X4 relay. If 35VDC is present and Comp and FM remain
energized, replace CB. 60 sec. after Comp and FM de-energize, confirm that GM and
X3 relay de-energize. If not, replace CB. Next, confirm DV energizes. If not, check for
24VAC at X5 relay #6 (W/O) to neutral (LBU). If 24VAC is not present, check for 24VAC
at X5 relay #2 (W/R) to neutral (LBU). If 24VAC is present at X5 relay #2 (W/R) and not
at #6 (W/O), replace X5 relay. If 24VAC is present at X5 relay #6 (W/O) to neutral (LBU)
and DV is not energized, check for 24VAC at X5 relay #6 (W/O) to X3 relay #5 (LBU)
and X5 #6 (W/O) to X3 relay #1 (Y). If 24VAC is present at X3 relay #5 (LBU) and not
at #1 (Y), replace X3 relay. If 24VAC is present, check DV coil continuity and replace as
necessary. If DV coil is good, check for crimped drain hose or clogged drain line.
Legend:
BC
–bin control;
CB
–control board;
Comp
–compressor;
CT
–control transformer;
DV
–drain valve;
FM
–fan motor;
GM
–gear motor;
HPS
–high-pressure switch;
LFS
–lower float switch;
UFS
–upper float switch;
WV
–inlet water valve;
X3
–compressor delay relay;
X4
–water control relay;
X5
–control relay;
X6
–safety
relay
