Thursday, January 13, 2011

hoshizaki ice machine beeping error code list?

Hoshizaki Ice Machine Troubleshooting


For 1 beep every 3 seconds:---

The HIGH TEMPERATURE SAFETY is activated, when the thermistor which is mounted on the suction line reaches a temperature of 127° F. When this occurs it will shut the unit down, trigger this alarm, and lock it out on a manual reset safety.

Some of the reasons for a High Temperature safety alarm are as follows.

You will find these possibilities included on the control board diagnostic label located in the compressor compartment.

Follow the instructions provided on the label to reset the alarm and check these areas to locate the problem.

First, check to see if there is a mechanical problem with the hot gas valve sticking open or with the control board relay sticking.

Check for a temperature differential across the hot gas valve. To check for a sticking relay, use a volt meter to check for voltage on pink wire, pin # 2 on the K1 connector.

Hot water migration can also cause this. This typically happens at night when the only piece of equipment requiring water flow is the ice machine. Hot water migration is a tough problem to find and to prove to the customer.
The best way to determine that this is happening is to place a temperature recorder on the inlet water line of the ice machine.
 The recorder will show when migration occurs. Usually hot water migration is due to a defective mixing valve in the existing plumbing. A good place to check is the pre-wash area at the dishwasher.

Another possibility is a stuck head master on a remote air cooled condenser unit operating in a high ambient
condition. The best way to check for this is to carefully touch the liquid line connection at the rear of the unit.
Also, check for heat at the inlet pipe to the receiver tank. If these areas are hot, the head master is likely
stuck in the bypass mode.The last possibility is a shorted thermistor. If the thermistor reads approximately 500 ohms or less the control board will lock out on this safety. A shorted thermistor will signal zero ohms and cause repeated shut down on HIGH TEMPERATURE SAFETY.

By following these suggestions, you should be able to resolve the problem that caused the HIGH
TEMPERATURE SAFETY alarm.
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For 2 beeps every 3 seconds:--

In this case, access the control box and you will find the orange LED marked 20 min. illuminated. By checking the control board
instructions label supplied with the board it can be
determined that the unit has run two consecutive 20 min.
harvest cycles.
Before the problem can be determined, the control board
must be reset. This can be accomplished by leaving
power applied to the unit and depressing the white reset
button in the corner of the board. The unit should now
start in the one minute fill cycle and be followed by the
initial harvest cycle which will last 20 minutes. A basic
check of this harvest cycle should narrow down the
possibilities which would cause a 20 min harvest cycle.
When the compressor starts, touch the discharge line and
the inlet and outlet of the hot gas valve. This will indicate
that the hot gas valve is opening, and that the discharge
vapor is hot enough for a timely harvest. If the outlet of
the valve is cooler than normal, the hot gas valve did not
open or is not opening enough to allow full hot gas flow.
If the hot gas valve does not open at all, a remote unit will
pull down in a vacuum because the liquid line solenoid is
closed in harvest. On smaller water-cooled units the
suction pressure will be close to that of a normal freeze
cycle. The high condenser pressure opens the water
regulating valve condensing the refrigerant and allowing
refrigerant flow to the TEV. The evaporator will frost
and the suction line temperature will never reach 48
degrees. In either case the suction line temperature never
reaching 48 degrees will cause a 20 min. harvest cycle.
A voltmeter should now be used to check for 115 volts to
the hot gas solenoid coil. If 115 volts is present the coil is
open or the valve body is stuck closed. If no voltage is
present the board is defective.
If the suction line temperature reaches 48 degrees check
the resistance of the thermistor. An open thermistor will
result in a consistent 20 minute harvest. The open
thermistor will need to be replaced. Take care to mount
the thermistor properly. The normal resistance of the
thermistor should correspond with the thermistor
resistance chart provided in the Tech Specs pocket guide.
Another possible cause is the TXV, or liquid line solenoid
leaking during the harvest cycle. If the TXV sensing bulb
is not secured on the suction line or if refrigerant is
exiting the expansion valve for any reason, it can cool off
the discharge vapor and cause an extended harvest
cycles. Check sensing bulb mounting and the operation of
the TXV in the freeze cycle by using normal diagnostic
procedures.
Refrigerant charge and compressor capacity is always a
question on long harvest cycles. If unit charge is in
question refer to the Tech-Specs pocket guide for normal
operating pressures and cycle times. An inefficient
compressor is probably the most difficult to troubleshoot.
Generally if a compressor is inefficient, suction pressure
will be higher than normal, discharge pressure will be
lower than normal, discharge vapor will be cooler than
normal and compressor amp draw will be lower than the
RLA. Use normal diagnostic procedures to determine a
weak compressor.
After checking these items , you should be able to resolve
the 20 minute harvest cycle shut down and resume
proper KM ice production.
For beeping 3 beeps every 3 seconds:---
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
necessary.
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.
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.
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*If you get 4 beeps every 3 seconds the connection between K-4 has a short circuit.
*If you get 5 beeps every 3 seconds the connection between K-4 has an open circuit.
To reset the safeties, depress the white alarm reset button while the board is beeping.
**BIN CONTROL TEST: The new bin control assembly mounts in the unit using
the two thumbscrews that mounted the thermostatic bulb. To test the control, allow the
unit to cycle into freeze for approximately 1 minute. Push the actuator to the right and
the unit should shut down within 3 ~ 5 seconds. When you remove your hand, the unit
should restart in the 1 minute fill cycle within 3 ~ 5 seconds.
If the unit fails to operate properly, first check the position of dipswitch number 7 on
the control board. This switch must be in the “ON” position for this bin control to
operate. Next check the resistance readings of the bin control assembly. With the
wiring harness disconnected from the board, check resistance across the red and black
wires on the red connector (harness end). When the switch is in the bin full position
you should read approximately 15.8 K-ohms. When it is calling for ice you should
read approximately 7.8 K-ohms. If the readings correspond to these, check for a
board problem. This type of failure however, is very rare and all other possible
possibilities should be checked before replacing the board.
If you do not get the readings above, you must determine which portion of the bin
control assembly is at fault. There are two basic parts of this assembly. They are, the
resistor wiring harness and the bin control switch assembly.
The bin control switch assembly, consist of the actuator and the switch. To test
disconnect the switch assembly from the wiring harness. This will isolate the switch
assembly. Using your ohmmeter, check between the black and white wires on the
connector from the switch (The red wire in the switch connector is not used). When
the actuator is in the ice making position you should read a closed circuit. When it is
in the bin full position it should read open. If the switch does not react correctly, you
should replace the switch portion of the assembly.
After the switch portion has been checked and is working properly the next component
to check is the resistor wiring harness. The resistor wiring harness must be disconnected from both the board and the bin control switch assembly. Again,
using your ohmmeter test across the black and red wires on the red connector of the
wiring harness. You should read approximately 15.8K-ohms. Now, read across the
white and black wires on the other end and you should read approximately 31.6 Kohms. If your readings do not correspond to these then replace the resistor wiring
harness.
Note: After the unit has started, it will only shut
down at the end of harvest or during the first five
minutes of the freeze cycle. The unit will not shut
down during the one minute fill cycle even when
the bin control is in the bin full position.
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For beeping 6 times:---
This is an indication that the unit is off on a low voltage safety. If the incoming voltage drops below 92 VAC+/- 5% the unit will de-energize the red LED and begin an audible alarm of six beeps every three seconds. The low voltage alarm is triggered by monitoring the secondary voltage of the transformer at the K2 connector on the control board. This alarm as well as the high voltage alarm will automatically reset when the proper voltage is restored.
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For beeping
7 beeps every 3 seconds:---

In this article we will
highlight the HIGH VOLTAGE SAFTEY which will be
signaled by 7 beeps every 3 seconds.
First, let’s discuss how the control board determines
that the machine is in a high voltage situation. This is one
by the control board monitoring the voltage at
the K2 connector or the secondary output from the
control voltage transformer. The proper voltage at the
output should be within 10.5 to 12.0 volts. If this
voltage increases due to primary voltage to the
transformer increasing to 142 vac. or higher, the unit will
shut down on a automatic reset high voltage safety. A
red LED on the board lights up when the control voltage
is correct. If the high voltage safety operates, this light
will be extinguished.
Now, let’s discuss the possible causes for this situation.
The first possibility would be if the supply power to the
unit was installed incorrectly (improper wiring). A
possible scenario could be that line voltage was supplied
to the neutral wire on a 208-230 volt unit or 208-230
volts is being supplied to a 115 volt unit. This would
cause the primary voltage to the transformer to be 208-
230 meaning that the secondary voltage will exceed the
boards threshold and shut down on the high voltage
safety.
The second reason is the existence of a “stinger leg” or
a “wild leg” in the voltage supply. This is a leg of power
that supplies over 150 vac. to ground. This leg, if
installed on the brown wire, will supply high voltage to
the transformer primary causing higher voltage on the
secondary. The unit will shut down on high voltage
safety. To operate the machine using a stinger leg, it
must always be connected to the black wire
(compressor circuit) in the unit junction box.
The third possibility is if the unit experiences a voltage
surge during normal operation. Any increase in the
incoming voltage will increase the control transformer
output. If this voltage surge reaches 142 vac. the unitwill shut down on the high voltage safety to protect
itself from damage.
It is important to note that the high voltage safety
protection will automatically reset itself when the wiring
is corrected or when the voltage returns to normal.
Check each of these items if the board signals 7 beeps.
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