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Uneven ice buildup in Scottsman C1448R
I’ve got a Scottsman C1448R ice maker. It’s been a bit of a problem child. But I’m at a loss now. Im getting harvest failures for a pretty obvious reason, the ice buldup varies across the height of the evaporator plate. When I manually harvest, the ice on the bottom of the plate is 1/4-3/8″ bridge while the top row of cubes still have a 3/8″ depression. Obviously the ice thickness sensor is continuing the freeze cycle even as the thickness at the bottom is too thick to harvest in a single cycle. Run 2 harvest cycles and the bottom 2/3 harvests and the top 1/3 stays in the grid.
The C1448R has dual plates, dual TXV valves and dual hot gas valves, and the problem is virtually identical across both plates- so I don’t think the problem is related to the tubing detaching from the plate. The high side (241 psi at 61 deg ambient (outside- its a remote unit)) pressure matches the documentation, the low side pressure gets pretty low- maybe 25 psi when ice is past the harvest point. Im pretty careful when adding Freon, but it’s not impossible some noncondensables have gotten in the system
I’ve never seen asymmetric ice cubes before with this unit.
I see no scale buildup.
Thanks for any suggestions.
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4 Replies
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Start with a full cleaning. Always! It sounds like you have a undercharge or line restriction from the remote. Your evaporators are starving for refrigerant. Your suction pressure should look like the graph on page 73 of this manual. Scotsman Prodigy Service Manual
Note that at the start of ice making the evaporator suction pressure is 80psi and that over 16 min it will drop to 40. You should have been having some service codes come up.
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Be aware that with remotes you can have a normal head pressure with a undercharge due to the headmaster in the condenser. Always feel your liquid line coming into the head from the remote. It should be near outside ambient. If its warmer, it’s a sure sign that the headmaster is bypassing compressor discharge gas to the liquid line.
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Thanks for the replies. Liquid line was somewhat cool to the touch- it was 61 outside, and the line was probably close. That’s actually cool, in my experience, when the system is running to spec the line often feels slightly warmer than outside conditions
It could be starved for refrigerant but the unit has a huge accumulator- After I added refrigerant (like 8-10 lbs-50% of a charge), it would follow the graph in the manual for 10-15 minutes, but suction pressure would continue to decrease as time went on w/o harvesting. Not sure this is even a problem- there was a thick bed of ice over 2/3 of the plate. I’ve seen what the system does when starved for refrigerent and it times out on the freeze cycle, and produces hollow cubes, but the entire sheet of ice looks to be the same thinkness. My guess is right now, the bottom cubes are 2x the weight of the top cubes.
Note the system has a slow leak. I’ve had 2 techs look at it besides myself, we can’t find the leak.
If I let it run, I get failed harvest codes, and occasional freeze timeout. When I manually harvest, I get a error code 6 (not a b)- its like a b with the top bar illuminated to make a clear 6.
IIRC the harvest pressures are off from the manual. Let me get them today and post. Regardless the incoming line is slightly warm as it enters the plate and you can see the melted water dripping. Same behavior on both plates (separate hat gas valves for each. )
I like the computer on the unit, but this has been a major problem child- I’ve put a new pump, harvest solenoid, water valve and door on it.
Thanks again, I’ll post harvest pressures tonight.
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You have a leak on the low side and the refrigerant has fractioned out. First you have to find the leak. A H10 g is the best detector for low leaks Soap bubbles work too. After finding and repairing the leak, replace the dryer and vacuum the system to 400 microns. Make sure it will hold the vacuum. Now recharge with a inverted new R404 refrigerant. The old is no longer R404. That’s the problem with the 400 refrigerants, They are blends, but not azeotropic blends that will not separate. Like the 500’s It’s common to see the line set connections leaking. I’ve cut out the speed connectors on many.
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