Troubleshooting a Hoshizaki Ice Machine Single Beep Alarm

What do you do if your Hoshizaki commercial ice machine is beeping at you instead of producing ice?  If you are an Easy Ice Subscriber – the answer is simple. Call us at 866-easyice and we’ll take care of it! :)

If it’s up to you to figure it out, here is our experience with Hoshizaki Single Beep Alarms:

Technically-speaking, the condition in the Hoshizaki ice machine that causes the High Heat Single Beep Alarm is the thermistor reaching 127 degrees F.  The most likely causes are:

  • 95% of the time a 1-Beep Alarm means that hot water has been delivered to the ice machine – a term most ice machine technicians will call “hot water migration.”
  • 3% of the time a failure of the hot gas valve will be the culprit.
  • On rare occasions, the thermistor will fail, giving a false reading.
  • It is theoretically possible the circuit board could fail, triggering a false alarm, but that hasn’t happened to us yet.

Hot Water Migration

Remember the statistics – 95% of the time, hot water makes it way to the ice machine and causes the Single Beep Alarm.

  • Confirming the Problem:  The simplest way to confirm this is happening is to touch any of the metal fittings along the water supply line right when the alarm starts.  That can be where the water line connects to the commercial ice maker, where the water line connects to the ice machine filter housing, or at the water line shutoff valve.  If you do this within 5 minutes of the start of the ice machine alarm, it should still be warm to the touch.  If you can’t seem to be around when the alarm goes off, an old plumber’s trick is to put a pat of butter or a dollop of Vaseline on one of the fittings.  At 70-80 degrees, the butter/Vaseline will hold it’s shape on the fitting and begin to liquefy at body temperature.  There are more scientific methods like irreversible temperature labels such as these from Tempil.
  • Tracing the Root Cause – If the water line is warm to the touch, then it should be easy to trace the line back to the offending device.  If not, then you can use multiple temperature labels in an attempt to track down the culprit.
  • Implementing the Fix – Installing check valves on the nearby sinks will usually solve the problem.  Sometimes the offending device is behind a wall or a little farther away, making it a little harder…but don’t give up hope, hot water doesn’t magically appear.  Stick with it and you will eventually find the source of the problem.

Hot Gas Valve Failure/Thermistor

Diagnosing a failure of the Hot Gas Valve is difficult because the HGV is inside the ice machine.  The job of the Hot Gas Valve is to pump hot gas in to the evaporator in order to “unfreeze” the ice cubes from the evaporator.  If the valve sticks open, it continues to pump hot gas in to the evaporator until the unit reaches 127 degrees F – shutting off the ice machine with the Single Beep Alarm.  The Thermistor is a thermometer inside the ice machine that will also require a skilled technician to both diagnose and repair the equipment.

Additional Information

Remember that the job of the alarm system is to protect the ice machine from serious damage.  The good news with the single beep alarm is that the ice maker can be reset and restarted quickly without significant concern of causing any machine damage.  The hot water migration problem is typically an intermittent problem, so it may take you a few times of tripping the alarm before you can locate the cause of the problem.  With a sticking Hot Gas Valve, the failure will generally repeat itself pretty quickly, so you won’t likely have to go through as many cycles to diagnose that problem.

Hot Water Migration Case Study

Hot water migration isn’t always straightforward, so it may take some perseverance to discover the root cause.  A very busy restaurant became a new customer of Easy Ice when they replaced their broken ice machine.  Three days later, the kitchen crew arrived at 8:00 am to hear the ice machine beeping.  The staff closed up the night before at 2:00 am with everything working great.  We reset the machine and it worked fine for a few days and the single beep alarm returned – again, between 2:00 am and 8:00 am.

The easy answer was to blame the new machine because one week earlier, the previous ice machine had been working without that alarm.  Since the alarm was being tripped between 2:00 am and 8:00 am, no kitchen staff members were present to hear the alarm begin.

To make a long story short, the cleaning staff was using the dish pit continuously to supply water for the floor scrubber, which tripped the alarm due to a mixing valve failure.  It tripped because when the ice machine pulled water in at the end of the freeze cycle (while the mixing valve was continuously engaged) the ice machine sucked in a large dose of hot water – enough to trip the alarm.  However, during normal daily operations the mixing valve was intermittently engaged so the ice machine only drew in a little hot water along with the cold water – not enough to trip the alarm.

The reason the problem started with the new machine?  Standards and technology have changed over the years.  In some cases older machines didn’t have the same sensitivity to incoming water.  They just took longer to make ice because they started off with warmer water.  In addition, today’s commercial ice machines use a lot less water and consequently, smaller variations get magnified, causing unexpected problems.

Ecolab and Reddy Ice help with free maintenance and ice machine repairsThe moral of the story is to stick to the troubleshooting process so you can rule out the most likely problems…leaving you with that one-in-a-million story we’d all like to tell!

Have more questions about Hoshizaki commercial ice machines or how our subscription program works? You’ll find your answers here.  Until next time…stay cool.

Your Friendly Neighborhood Iceologists