I have a Manitowoc QM45 that shut off for no reason. When I turned it on after I cleaned it, it ran for many cycles, I lost count, and had filled the ice bin. When I went for the ice the next day, I found that the machine was off and the switch was in the on position. I switched the machine off for a few seconds and then it on and everything was working as expected. I watched it for about an hour and it went through many cycles without issue, so I let it run. When I checked it the next morning, it had shut off.
Is there additional troubleshooting I could do to narrow down what may be causing this? Or, is there a fix I can perform?
First off, when it does it check that the ice damper is fully back so that the magnetic switch is closed. If it moved back the machine will restart in about 3 minutes. If it does not restart, watch the harvest light on the control board. Shut to machine off and then back on after about 10 seconds. The Harvest light will blink either 1 or 2 flashes. This will indicate whether it is a long freeze or long defrost that is the problem.
Also make sure the condenser is clean and the fan is running at full speed.
What is the ambient temperature the machine is in? What is your bridge thickness?
Make sure the water float level is correct. I suspect you have a long harvest alarm. should harvest in about 2 to 3 min. Also if you use a ice machine cleaner other than Manitowoc, the evaporator get's a fine etch that slows the harvest or completely holds the ice from falling with age.
Behind the pump there is a siphon cap to remove minerals each cycle. If the water level is to low, When the pump stops and the water drains back to the sump it gets to a precision height that starts a siphon. After a dozen or so cycles without draining the sump the minerals build up and cause a hanging sheet. As well as coating the evaporator and requiring a recleaning.
Thank you for your help. The ice machine is working well. I walked through all of your suggestions and couldn't find anything wrong or not working. So, I adjusted the bridge and made it smaller. That seemed to do the trick. The ice machine has been running for three days.
You will find that the cleaning of the thickness sensor is quite critical on this machine. It's very important to scrub it in ice machine cleaner, them rinse well and thoroughly dry. any residual acid on it is conductive and will give a false sense.