F) Led Lights And Audible Alarm Safeties - Hoshizaki KM-251BAH Service Manual

f) LED Lights and Audible Alarm Safeties

The red LED indicates control voltage (10 to 12V at K2) and will remain on unless a
control voltage problem occurs. At startup a 5 second delay occurs while the board
conducts an internal timer check. A beep occurs when the control switch is moved to the
ICE position.
The green LEDs 1 through 4 energize and sequence from initial startup as listed in the
table below. Note that the order of the LEDs from the outer edge of the board is 1, 4, 3,
2. For more information, see "II.B. Sequence of Operation."
Sequence Step
1 Minute Fill Cycle 4
Harvest Cycle
Last 50 seconds of harvest, HWV de-energizes and PM energizes
(LEDs 1, 3 and 2 are on)
Freeze Cycle
After the first freeze following startup and every 10th cycle thereafter, Comp, HGV, and PM
are energized for 10 seconds between freeze and harvest (LEDs 1, 3 and 2 are on)
The built in safeties shut down the unit and have alarms as listed below.
No. of Beeps
(every 3 sec.)
1 High Evaporator Temp.
(temperature > 127°F)
2 Harvest Backup Timer
(harvest > 20 min. for two
cycles in a row)
3 Freeze Timer
(freeze > specified setting
for two cycles in a row)
Timer is factory set using
S4 dip switch 9 & 10
To manually reset the above safeties, press the alarm reset button with the power
supply on.
6 Low Voltage
(92Vac ±5% or less)
7 High Voltage
(147Vac ±5% or more)
Legend: Comp–compressor; FMS–self-contained fan motor; FWV–freeze water valve;
HGV–hot gas valve; HWV–harvest water valve; PM–pump motor; TXV–
thermostatic expansion valve
Energized
LED
Components
FWV
1, 4 and 2 HWV, HGV,
Comp
1 (and 4 at Comp, PM,
refills) FMS (FWV
at refills)
Type of Alarm
(53°C)
Time LEDs are On
Min.
2 minutes 20 minutes 3 to 5 minutes
5 minutes freeze timer
setting
Check for harvest problem (stuck HGV or
relay), hot water entering unit, or shorted
thermistor.
Check for open thermistor, HGV not
opening, TXV leaking by, low charge or
inefficient Comp
Check for a float switch stuck closed (up),
HWV or FWV leaking by, HGV leaking by,
TXV not feeding properly, low charge, or
inefficient compressor.
Red LED will turn off if voltage protection
operates.
The control voltage safeties automatically
reset when voltage is corrected.
13
Max. Avg.
60 seconds
30 to 35 minutes
Notes