Hoshizaki KM-501MAH User Manual
8
f) LED Lights and Audible Alarm Safeties
The red LED indicates proper control voltage 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 short beep occurs when the power switch is turned OFF.
The green LEDs 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 , 4, 3,
. For more information, see "II.B. Sequence of Operation."
problem occurs. At startup a 5 second delay occurs while the board conducts an internal
timer check. A short beep occurs when the power switch is turned OFF.
The green LEDs 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 , 4, 3,
. For more information, see "II.B. Sequence of Operation."
Sequence Step
LED
Energized
Components
Time LEDs are On
Min.
Max.
Avg.
Minute Fill Cycle 4
WV
60 seconds
Harvest Cycle
, 4, and
WV, HGV,
Comp, FMR
Comp, FMR
minutes 0 minutes 3 to 5 minutes
Freeze Cycle
Comp, PM,
FMR/FMS,
LLV
FMR/FMS,
LLV
5 minutes freeze timer
setting
30 to 35 minutes
Reverse Pump Out , 3, and
Comp, HGV,
PM, FMR
PM, FMR
0 seconds 0 seconds factory setting
The built in safeties shut down the unit and have alarms as follows:
No. of Beeps
(every 3 sec.)
Type of Alarm
Notes
High Evaporator Temp.
(temperature > 7°F)
(53°C)
(temperature > 7°F)
(53°C)
Check for harvest problem (stuck HGV or
relay), hot water entering unit, stuck HM,
or shorted thermistor.
relay), hot water entering unit, stuck HM,
or shorted thermistor.
Harvest Backup Timer
(harvest > 0 min. for two
cycles in a row)
(harvest > 0 min. for two
cycles in a row)
Orange LED marked H TIMER lights up.
Check for open thermistor, HGV not
opening, TXV leaking by, low charge, or
inefficient compressor.
Check for open thermistor, HGV not
opening, TXV leaking by, low charge, or
inefficient compressor.
3
Freeze Timer
(freeze > specified setting
for two cycles in a row)
Timer is factory set using
dip switches 9 & 0
(freeze > specified setting
for two cycles in a row)
Timer is factory set using
dip switches 9 & 0
Yellow LED marked F TIMER lights up.
Check for F/S stuck closed (up), WV
leaking by, HGV leaking by, TXV not
feeding properly, low charge, HM not
bypassing, or inefficient compressor.
Check for F/S stuck closed (up), WV
leaking by, HGV leaking by, TXV not
feeding properly, low charge, HM not
bypassing, or inefficient compressor.
To manually reset the above safeties, press the alarm reset button with the power
supply on.
supply on.
6
Low Voltage
(9Vac ±5% or less)
(9Vac ±5% or less)
Red LED will turn off if voltage protection
operates.
The control voltage safeties automatically
reset when voltage is corrected.
operates.
The control voltage safeties automatically
reset when voltage is corrected.
7
High Voltage
(47Vac ±5% or more)
(47Vac ±5% or more)
Legend:
Comp–compressor; FMR–remote fan motor; FMS–self-contained fan motor;
F/S–float switch; HGV–hot gas valve; HM–headmaster (C.P.R.); LLV–Liquid
Line Valve;
PM–pump motor; TXV–thermostatic expansion valve; WV–inlet
water valve