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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a Scotsman Prodigy. The ice is getting hung up in the

Customer Question

I have a Scotsman Prodigy. The ice is getting hung up in the harvest mode and it seems to me that the left side of the ice grid is not melting enough to brake free and fall. We had a tech out and he replaced the ice thickness sensor and the harvest assist solonoid. When that didn't work he said that we would have to replace the entire "grid" as he called it referring to the evaporator for around $2500. I have spent a great deal of time watching it and resetting it to see where it gets stalled.
It seems to me that the left side of the evaporator is not melting enough as the hot gas runs through the serpantine and holds up the entire sheet of ice cube. Is it possible to do it my self and replace the hot gas solonoid? Just guessing at this point hoping not to spend $2500.
Submitted: 1 year ago.
Category: HVAC
Expert:  shaithus1 replied 1 year ago.

Hi.. let me see if I can help...

It sounds like the grid itself may have a blockage...

When the hot gas solenoid opens, it sends hot gas through the grid to melt the ice and harvest.

When the technic***** *****ged out the solenoid valve, did he change the whole valve or just the coil?

Did he place it under a vacuum? Did he purge the system?

His guages should have indicated that there was a blockage when harvest started because pressures would have increased from no gas flow...

It pretty obvious if you can see the ice sheet move up to a certain point.... but... let me be clear... if the blockage is there, you would see a freeze line on the grid. If hot gas wont flow neither should the cold, unless the blockage is partial and metering is occuring.

Unless you are a trained and licensed refrigeration tech, you should no attempt to repair the refrigeration portion of the machine.

Is the company you used an authorized agent of Scotsman? I know our techs are and Scotsman provides us training and technical support on their equipment.

The evaporators can be very expensive to change out and depending on the age of the ice machine, replacement may be the better option.

The ice thickness sensor would not effect only part of the grid.... the ice thickness sensor tells the machine to harvest at a set thickness.... the fact that the ice is not coming away from the grid evenly, indicates an issue in the grid...not the sensor.

Expert:  shaithus1 replied 1 year ago.

Can you give me a model number so I can pull up a schematic and verify any other potential issues.


Customer: replied 1 year ago.
Please review my earlier comment. The technician did not replace the solenoid or valve (hot gas). It is my conclusion after watching, that the cubes are not melting enough to free themselves in the harvest cycle. Can I send u pictures?
Customer: replied 1 year ago.
Co 330MA -1A
Expert:  shaithus1 replied 1 year ago.

. I'm sorry... he did replace the harvest assist solenoid...

I wont get any pictures...

Ok.. per the manual....

When the harvest cycle begins, the controller shuts off the fan motor, switches on the hot gas valve, and through a parallel circuit, the harvest assist solenoid. After a few seconds the purge valve opens and water is drained from the reservoir. Based on either the automatic purge or manual purge setting, the pump and purge valve will be switched off at a time determined to have drained enough water for that setting. The inlet water valve will open to fill the reservoir anytime the mid length probe is uncovered, which occurs during the reservoir drain cycle. Harvest continues as the hot discharge gas flows into the evaporator serpentine, heating up the evaporator. At the same time the harvest assist solenoid is pushing against the back of the ice slab. When the ice releases from the evaporator, it harvests as a unit, and the harvest assist probe provides some additional force to push it off. When the ice falls off it will force the curtain(s) open. An open curtain during the harvest cycle signals the controller that the evaporator has released its ice. If this is a single evaporator machine the controller will terminate harvest. If it is a two evaporator machine, the controller will continue harvest until both curtains have opened. If one curtain remains open, the controller will shut the machine down on bin full. Anytime harvest is complete the hot gas valve and harvest assist are shut off. The harvest assist pin returns to its normal position by spring pressure.
If the curtain(s) re-close after harvest, the freeze cycle will restart.

So... if he changed the harvest assist the problem may be in the hot gas valve itself.... you might be seeing only the harvest assist working...

You will need an EPA licensed technician to come back out and check the operation of the hot gas valve...