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Thread: Manitowoc qy1894n3
02-27-2012, 07:00 PM #1Professional Member
- Join Date
- Sep 2011
- Fayetteville, NC
Brief history about this unit. It was put in two years ago and from what they tell me, it's always sounded like crap. This is the loudest compressor I have ever heard.
The problem coming up is that this unit is staying in harvest past the 3.5 minutes harvest limit and going back into freeze cycle. The unit has been cleaned. Evap isn't in great shape but I have seen worse still in working order.
The evap was sprayed with food grade silicone to aid in the sheet dropping. But it isn't helping enough to get the sheet to drop before 3.5 minutes. Its dropping on average 10 seconds after the restart of the freeze cycle.
The pressures spec out according to the manitowoc handbook in the harvest cycle and the freeze cycle. But for the last minute or two of the freeze cycle the suction is about 3-4 psi below manitowoc specs of 40-25 psi.
Book calls for 150 degrees six inches from the compressor during the end of the freeze cycle right before harvest. I measured 143 degrees.
Both harvest valves are energizing during harvest and the suction is 73-75 psi the entire time. Head pressure is about 165 psi.
From what I can tell others have worked on this equipment before. There are dates wrote on components inside the unit. Compressor changed out in 2010, filter dryer changed 2011.
Here is another kicker that has me acting silly. This machine is making wonderful ice. From start to finish, about 15 minutes. Specs say freeze cycle should be 10-11 minutes with 1-2.5 minutes of harvest.
But during operation the compressor appears to be getting liquid refrigerant back. If the txv was slightly flooding the evap, wouldnt that keep my suction pressure out of spec? In a nut shell the top part of the compressor is getting frost on it. LIke the whole top of the compressor.
Any insight would be appreciated. I have spoken to others at the company that I work with and thought that this forum would be able to offer different views on the situation.