Hoshizaki Ice Machine Model KM-500MAF
(Quated From Hoshizaki Technical Bulletin)
An alarm code of 3 beeps
every 3 seconds means that the control board has shut
down on the 60 minute freeze cycle back up timer.
The “E” control board has a 60 minute timer that starts at
the beginning of the freeze cycle. If the float switch fails
to open and start the next harvest within 60 minutes, the
board will automatically start the harvest cycle. If this
occurs in two consecutive cycles, the control board will
shut the unit down on the manual reset, freeze cycle
back- up timer. The yellow fault LED marked “60 min.”
will illuminate. This safety is designed to help prevent a
freeze up of the evaporator.
Once you have identified the 60 minute alarm, there are
several things to check. Reset the alarm by depressing
the white reset button to the right of the fault LED’s.
This must be done with the power “ON”. Now check the
float switch to see if it is stuck in the up position. A stuck
float can occur if scale is present on the reed switch
shaft inside the housing. To check it, drain the water
reservoir, unplug the black float switch connector (K5)
from the control board and check it with an ohm meter
for a closed switch (zero ohms). If the float switch is
sticking, clean it with ice machine cleaner or replace it as
An inlet water valve which is slowly leaking by during the
freeze cycle can cause a 60 minute alarm. If the inlet
water valve is stuck wide open, it is unlikely that any ice
will form on the evaporator. Check for a slow leak by
allowing the unit to cycle into the freeze cycle and
disconnecting the hose at the outlet of the water valve. If
water leaks by during the freeze cycle, the water valve
diaphragm is likely damaged or the small diaphragm bleed
port is clogged with scale. Clean the bleed port or replace
the diaphragm or entire water valve as necessary.
(I Recommend to get a refrigeration tech for this part).
Another possibility is a refrigeration system problem. You
should use normal refrigeration diagnosis procedures to
check for one of these problems. If the thermostatic
expansion valve is not feeding properly or the refrigerant
charge is low, the evaporator will not form ice as it should
and a long freeze cycle will occur. This could also be the
result of the hot gas valve not closing completely during
the freeze cycle or if the compressor valves are weak or
inefficient. An inefficient compressor however, will
usually show up first on the KM model through a longer
than normal harvest cycle. This is because of cooler
than normal discharge gas. Use proper refrigeration
practices to repair a refrigeration system problem.
While these are not the only reasons for a 60 minute
freeze cycle, they are the most common and should be
checked to resolve a 3 beep/yellow fault LED alarm.
Feb 27, 2008 |
Hoshizaki Commercial Freezer KM-500MAH