Hoshizaki KM-500MAH Service Manual page 16

The green LED's 1-4 represent the corresponding relays and energize and sequence 5
seconds from initial start-up as follows:
Sequence Step
1 Minute Fill Cycle
Harvest Cycle
Freeze Cycle
Reverse Pump Out
{LED 1 – Comp; LED 2 - HGV/CFM; LED 3 – PM; LED 4 - WV}
The built in safeties shut down the unit and have alarms as follows:
1 beep every 3 sec. = High Evaporator Temperature >127 ° F.
Check for defrost problem (stuck HGV or relay), hot water entering unit, stuck
headmaster, or shorted thermistor.
2 beeps every 3 sec. = Defrost Back Up Timer. Defrost >20 minutes.
Orange LED marked 20 MIN energizes.
Check for open thermistor, HGV not opening, TXV leaking by, low charge, or inefficient
compressor.
3 beeps every 3 sec. = Freeze Back Up Timer. Freeze > 60 minutes.
Yellow LED marked 60 MIN energizes.
Check for F/S stuck closed (up), WV leaking by, HGV leaking by, TXV not feeding
properly, low charge, or inefficient compressor.
4 beeps every 3 sec. = Short Circuit between the K4 connection on
Machines
the control board and the bin control relay. Check connections and
with
replace wire harness if necessary.
mechanical
bin control
5 beeps every 3 sec. = Open Circuit between the K4 connection
ONLY
on the control board and the bin control relay. Check connections and
replace wire harness if necessary.
To manually reset the above safeties, depress white alarm reset button with the power
supply ON.
6 beeps every 3 sec. = Low Voltage. Voltage is 92 Vac or less.
7 beeps every 3 sec. = High Voltage. Control voltage > 147 Vac ±5%.
The red LED will de-energize if voltage protection operates.
The voltage safety automatically resets when voltage is corrected.
The Output Test switch "S3" provides a relay sequence test. With power OFF, place S3
ON and switch power to ICE. The correct lighting sequence should be none, 2, 3, 4, 1, & 4,
normal sequence every 5 seconds. S3 should remain in the "OFF" position for normal
operation.
LED's on Length:
LED4
LED1, 4, & 2
LED1
LED1, 3, & 2
16
Min. Max.
2 min. 20 min.
5 min. 60 min.
10 sec. 20 sec.
Avg.
60 sec.
3-5 min.
30-35 min.
Factory set.