Troubleshooting a Scotsman Ice Machine

/ Ice Machines, Troubleshooting / July 3

Troubleshooting a Scotsman Ice Machine

Scotsman ice machines are fixtures in restaurants, hotels and other establishments worldwide. With over 300 models of makers, dispensers and bins that offer a wide variety of ice in unique shapes and textures, it’s no surprise why.

When these commercial ice makers aren’t running properly, pinpointing the exact problem can be challenging. But don’t worry! Below are some common issues troubleshooting tips a Scotsman ice machine.

Power Issues

If the lights and indicators are off and there are no audible sounds are coming from the machine, the power could be off. Here are a couple of clear indicators.

  • Power switch is off or cord is unplugged – Before you start trying to diagnose any problems, check if the power switch is off. This potentially will save you the stress of having to dive deeply into your machine. Also, see if the power cord was unplugged or accidentally knocked out of the outlet. If you notice rips or damage to the cord, replace it with a new one.

  • Blown fuse or tripped circuit – If the power switch is on but there still is no power, you could have a blown fuse or tripped circuit in your building’s fuse box. Reset the circuit breaker or replace the blow fuse.

Not Making Ice or Making Too Much Ice

When your machine won’t make ice or makes too much ice, here are some issues that could be the culprit.

  • Leaking – Leaks can affect the production of ice in your unit. Check if there is leaking through the hot gas, thermal expansion or inlet water valves. In some cases, leaks could be coming from worn out fittings, drains and tubing.

  • Blocked condenser – When the freezing and harvest cycles are too long, there might be dirt or scale buildup in the condenser or air filter. Cleaning both components should help increase production. If you notice damage to either one, make sure to replace it immediately.

  • Low room temperature – Most Scotsman ice makers won’t produce ice when the temperature is below 55 degrees Fahrenheit. Make sure the machine is in a room or setting that is warmer.

  • Misleading “Bin Full” light – If you see the “Bin Full” light is on but the bin isn’t full, the ice sensors might need to be cleaned or replaced.

  • Faulty thermistor – A bad thermistor usually causes the bin to fill with too much ice. Use a multimeter to test the thermistor. If the multimeter reading comes back negative, replace it.

Ice is Melting or Flawed

  • Excess water melting ice – If you water keeps running into the bin, it can melt the ice. Excess water typically is caused by drainage problems. See if there is a blockage in the drain or tubing. Leaks from various valves, fittings and components also can cause a water buildup that melts ice (see “Leaking” in section above for more details).

  • Misshapen ice – While leaking from the curtain or pump hoses can affect the shape your ice, there are other key factors to look for. There could be an insufficient water supply coming into your unit or the water filters might be dirty. Also, defective spray jets might be dirty or broken, causing cubes to be misshaped or a fraction of its intended size.

Machine is Noisy

Like most ice makers, Scotsman usually have a soft humming sound when in operation. The abnormal noises below might indicate an issue.

  • Squealing sound – If your machine is making a high-pitch squeal, see if there are any tight or dry bearings in the motor pump. Lubricating the bearing should help eliminate the sound.

  • Grinding sound – This noise usually stems from the unit’s pump. Try cleaning the surrounding area if there is dirt or scale buildup. If that doesn’t help, you may need to replace the pump.

  • Rattling sound – Rattling noises could be attributed to a couple of factors. First, see if there are loose screws on the back panel and fasten them. If that’s not the case, check the pump fan’s blades. A damaged fan blade could be causing the loud noise.

How to Reset a Scotsman Ice Machine

Like a computer or smartphone, sometimes resetting your Scotsman ice machine is all it takes to get things back in order below are steps that work on most models. Find the control panel on your unit, and locate the red button on the panel. Press down and release the button to power the machine down. All the indicator lights should turn off. Then, locate the green button and hold for a second before releasing. The machine should turn back on and start the reset process.

If you need more info on troubleshooting a Scotsman ice maker, check out our selection of manuals and diagrams by model. In some cases, you’ll need to contact an authorized service agent to resolve the issues with your machine.


  1. praveen says:

    our scotsman sb530 ice mechain triping always.there showing high can solve this problem

  2. Parts Town Admin says:

    Hi, Praveen!

    If the unit is constantly locking out on high pressure, the most likely cause would be a dirty condenser coil. This should be cleaned a minimum of every 3 months as part of preventive maintenance.

    If the condenser is located outside, the fan motor may have a fan-cycle switch in line with it to maintain pressures during low ambient temperatures. If that switch is stuck open, the fan will not run and cause the same issue.

    The fan is also cycled off during a “harvest” cycle, usually controlled by the main control board. If the board is failing to send power to the fan motor, the unit will trip on high pressure.

    The motor itself might have failed as well.

    Hope this helps!

  3. Geoffrey Basiamisi says:

    i have machine scotsman ice maker model MV 306 sometimes it shows full bin til i switch the power off and on again ,what can be the problem .im really struggling to make it work

    • Many Scotsman machines use a water curtain to shut the machine down when the bin is full. There’s a magnet attached to the curtain, and will break a circuit when pulled away from the ice plate. That magnet / switch may be out of alignment, the controller may be faulty and not reading the signal from the magnet/ switch, or you could have small pieces of ice holding the curtain open because they didn’t drop into the bin. If the sheet of ice does not completely drop into the bin during a harvest, you can try to descale the machine and clean the condenser coil. If that doesn’t work, you might have a refrigeration issue that would require a technician to diagnose.

  4. Judy says:

    My Scotsman model DCE33A-1SSD is always running. It makes ice but it is never full. We can hear the water filling and the ice falling and it never stops. Can you tell us why it never is full and is always running?

  5. craug says:

    On a model CO330 ice machine, is there any way to change the time out length on the harvest cycle. My machine times out before the harvest is complete. It only needs to be about 60 seconds longer.

    • There is no way to adjust the length of the harvest on this unit listed in the service manual. You can try bringing the ice thickness probe closer to the evaporator coil, as the bridge being too thick might result in a failed harvest. It’s also important that no scale is present on the coil, which can also cause a failed harvest. It’s possible the mechanical harvest assist solenoid has failed as well. This solenoid physically pushes on the ice during the defrost to help it drop into the bin. If the ice is not forming evenly, you might also have a refrigeration problem.

  6. Frank Clay says:

    We have a Scotsman DCE33 Ice machine. I cleaned the machine because the ice was mostly white. We installed a new water filter, the kind we always use and the cubes are still white. Thank you for your help.

    • The cloudiness in the cubes is possibly due to air being trapped in the water as the ice forms. You can visually inspect the hoses for tears and make sure the machine is filling with enough water. If the unit is not filling with enough water, the pump with force air through the hoses with the water and cause the ice to not be clear.

  7. My Scotsman ice machine is not making ice, and all of the water is instead pouring into the bin itself. Troubleshooting tips?


    • The cloudiness in the cubes is possibly due to air being trapped in the water as the ice forms. You can visually inspect the hoses for tears and make sure the machine is filling with enough water. If the unit is not filling with enough water, the pump with force air through the hoses with the water and cause the ice to not be clear.

  8. Robert says:

    Would cloudy or faulty bin eyes cause a Scotsman ice machine to go into premature harvest?

    • Not directly, no. Most Scotsman ice machines use an ice thickness probe to tell the controller when to switch to harvest mode (when the ice builds out enough to touch the probe, the machine will harvest). The ice being cloudy shouldn’t affect the signal to ground. Cloudy ice could be an indicator that you need to clean the machine, though, which COULD cause the board to harvest prematurely. The signal can reach ground through the build-up on the probe if it’s bad enough. The probe is typically located at the top of the evaporator plate, hanging on 2 hinge pins. Inspect for cleanliness and check that the depth is adjusted properly.

  9. Jurgen says:

    I have an ACM126AS unit ! After cycling for about 25 minutes , unit goes into harvest mode and aproximately 1 min the system goes into High pressure shutdown ( this being after it has dropped its making ) My condensor is clean and the fan is working ! Gas levels on my gauges appear to be fine ! How can I rectify this problem !

    • What is your head pressure when it shuts down of high pressure safety?

      If the pressure control is opening prematurely, replace the pressure control. If the pressure control is opening when it should, it’s possible the condenser fan motor is not energizing after the harvest (it is typically cycled off during a harvest mode). This could be due to the motor overheating / failing, or the board not sending voltage to the motor. If the unit drops ice, it’s not likely to be an issue with the hot gas solenoid.

  10. Kenny Lang says:

    I have a Scotsman CME506 and I just replaced the water pump. In turning the machine back on, now the pump runs continuously without stopping and wide open, right into drain and cascading down the coils in large quantity, therefore not making ice. The pump and supply never stop. The new pump bottom is taller than the old, even though it is same exact part number. So the pump tray sits up about 3/8″ as does the float. Is this a controll board issue, float, or ??

    • Check to see if you have voltage at the water inlet valve before replacing anything. If the pump failed due to lack of maintenance, it’s very possible the float is stuck or contacts are dirty as well. If you have voltage at the water inlet valve, check to make sure your float contacts are opening and closing properly before condemning the control board. It sounds like the pump is working fine now, and the issue is just fresh water constantly being added to the sump.