Hoshizaki DCM-271BAH-OS Service Manual page 11

5) Startup–CB "POWER OK" LED is on. Turn on the power supply, then move the power
switch to the "ON" position. CB "POWER OK" LED and IS green LED turn on.
Diagnosis CB "POWER OK" LED: Check that CB "POWER OK" LED is on. If not,
check for 115VAC at control transformer black (BK) wire to neutral (W). If 115VAC is
not present, check the power switch, power cord connection, and breaker. If 115VAC
is present, check control transformer continuity. Replace as needed. Next, check for
24VAC at control transformer red (R) wire to neutral (LBU). If 24VAC is not present,
check control transformer continuity. Replace as needed. If 24VAC is present, check
24VAC 1A fuse. If fuse is good, check for 24VAC at CB K8 #1 (W/R) to CB K8 #2
(LBU). If 24VAC is not present, check control switch continuity. If open while in the
"ICE" position, replace control switch. If 24VAC is present and "POWER OK" LED is off,
replace CB.
6) Fill Cycle – "WTRIN" LED is on. Reservoir is empty and LFS and UFS are open.
90-sec. FT starts. WV energizes and fill cycle starts. LFS closes. Nothing occurs at this
time. Reservoir continues to fill until UFS closes. When UFS closes, WV de-energizes,
90-sec. FT is terminated, CB "WTRIN" LED turns off, 30-min. FZT and 5-sec. GM delay
timer start. If UFS remains open longer than 90 sec. after LFS opens, FT exceeded
and CB sounds a 1-beep alarm. WV remains energized until UFS closes. Alarm resets
automatically when UFS closes. Diagnosis: If reservoir is empty and "WTRIN" LED is
off, confirm LFS status. See "II.E.1. Float Switch Check." If LFS is open and "WTRIN"
LED is off, replace CB. If "WTRIN" LED is on, check that the reservoir fills. If not, check
water supply line shut-off valve, water filters, and WV screen. If "WTRIN" LED is on and
WV is off, check CB K2 #8 (O) to a neutral (LBU) for 24VAC. If 24VAC is not present,
check CB K2 #9 (W/R) to a neutral (LBU) for 24VAC. If 24VAC is present on CB K2
#9 (W/R) and not on CB K2 #8 (O), replace CB. If 24VAC is present on CB K2 #8 (O),
check continuity through WV solenoid. If open, replace WV. If WV is energized and refill
exceeds FT with no water in the reservoir, check for DV leaking. If reservoir is full and
overflowing check for open UFS. See "II.E.1. Float Switch Check." If UFS is closed,
check that WV de-energizes. If not, check CB K2 #8 (O) to a neutral (LBU) for 24VAC.
If 24VAC is present, replace CB. If WV de-energizes and water continues to fill the
reservoir, replace WV.
Note: Low Water Safety– If UFS remains open 90 sec. after WV energizes, a 1-beep
alarm sounds. This alarm resets automatically once UFS closes.
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