Scotsman not freezing

[justroln]

I dont usually work on Icemakers but the guy who does is out sick for the week, so the boss sends me out to look at a customers scotsman cme 256 air cooled. The unit turns on and begins its freeze cycle, but dies approx thirty minutes in. With a steady refrigeration diagnostic light. Talked to two people at scotsman tech support, one who told me its a temp sensor and the other who tells me its a refrigeration problem.
Any help would be greatly appreciated.

[bama 101]

http://www.scotsman-ice.com/support/MANUALS/CMCUBED/1-2PLTAW.PDF

hope this link helps........

[primmers]

30 minutes is the problem..water level may be too high to let it go into harvest..you may have a leaky water valve..

[justroln]

Thanks for the replies, checked the valve and its not leaking.

[Steve Bukosky]

I don't know Scotman but some other brands have a failsafe lockout if the freeze time exceeds a certain time. 30 minutes for a freeze cycle is too long for what I'm familiar with so I wonder if the cube bridge is getting too large and the ice sensor is not working or if the cubes are slow to grow which would be a refrigeration problem. Some machines go into harvest based on time (Ice-O-Matic) and some have sensors (Manitowoc)

If the cubes are not freezing properly, I'd check by feel to see if the harvest valve (hot gas solenoid) is leaking. Then I'd check the pressures to see if the suction is pulling down adequately and superheat in normal range of the TXV. A unit can get low on charge just by the hose losses from checking the pressure. Use short hoses. Leave the 60"ers for the big stuff.

[jlkelly]

Scottsman machines suck and are inefficient! With that said what is your suction pressure right before it dies. you should be at about 29lbs or < right before harvest.

Check for refrigerant leak....leaky hgv.....temp sensor.

Look to see if you have ice and how much when this happens.

[chiller mekanik]

The last Scotsman I worked on did about the same thing. I had the red light on as well. I checked the sensor with a meter against the chart, decided my sensors were ok. Put unit on line again & pressures were good for about 10 - 15 minutes then the suction pressure would tank & about 15 - 20 minutes later the module would take it off line. While my pressures were good the txv appeared to be feeding good. When my suction pressure tanked the distibutor lines would get warm after several minutes. I installed a new txv & my problems were over. Hope this story helps!