Aquasnap Chiller with micro channel condenser coils

[Eastcoasttech]

So all 3 are sweating?

No just the bottom ones are sweating.

[CCSPIERCE]

Try removing 5 # of the refrig charge and see what happens.

[Eastcoasttech]

I shorted the charge at first the result was slightly different and it ran okay until the last compressor came on. It shot right up from 450ish to above 600 and a diag showed up.

[Dallas Duster]

I think you need to run as many compressors as you can to stay online and get a log of temps and pressures and subcooling.

Edit: does the unit have a motor master?

I shorted the charge at first the result was slightly different and it ran okay until the last compressor came on. It shot right up from 450ish to above 600 and a diag showed up.

[CCSPIERCE]

Eastcoast help me out here. Is this "restriction" symptom occuring in one coil or more than one coil in the parallel pack? That model vintage had some issues with dataplate charge on the lbs per circuit. Dallas i think you are correct, need to get stabilized and check subcooling, superheat, fan amps, etc. Incidentally i have had to remove 10 to 12 percent of nameplate to get the charge down to where the hpco wouldn't cut out

I bought an expensive digital gauge that records and holds min/max pressures. I was amazed at the momentary spike at start up for a hot set of coils that were restarting after a short stop (cycling). 600 + psi for just a second at start up, reduced charge to calm it down and get some subcooling.

This sounds like liquid backing up somewhere, you did say this is a three pass coil?

[Eastcoasttech]

Well first I pulled 83 # of gas out. We had the coils replaced and recharged with 80 lbs because that's all we had at the time. There are four compressors and the problem is across all sets and if the coils are six feet across then two feet get warm and the remaining four stay cold. Walking on top of the unit, the right side farther away from the header is blowing cold while the header side blows warm/hot. It's almost like the refrigerant isn't making it across to the other side and only going in and out like the coil is "backwards". The display shows 11 degrees SH

[Dallas Duster]

All coils meaning the one`s your guys changed out plus the other circuit??

Well first I pulled 83 # of gas out. We had the coils replaced and recharged with 80 lbs because that's all we had at the time. There are four compressors and the problem is across all sets and if the coils are six feet across then two feet get warm and the remaining four stay cold. Walking on top of the unit, the right side farther away from the header is blowing cold while the header side blows warm/hot. It's almost like the refrigerant isn't making it across to the other side and only going in and out like the coil is "backwards". The display shows 11 degrees SH

[Eastcoasttech]

The circuit in question is the only circuit on this machine that has issues. Circuit A. B circuit hasn't had a chance to run as yet. But I'm sure it will as well. There are three machines at this facility but only one required the coil change out.

[chilbrig]

Don't know why your coil would be sweaten, but I bet you are over charged. 425 with only one compressor running is way to high. You can over charge very easily with a Micro Coil. IF you are weighing the charge in and it calls for 86 lbs. I would only put in 82. One pound over will really jack your head up. There should be a charging procedure in the IM manual that works a lot better than weighing the charge in.

[supertek65]

that is confusing???

the bottom most suction one??

I have several 30rb chillers and have changed many coils and hoy gas tees!


ONE tiny tiny tiny little piece of dessicant from a dryer or a grain of sand will restrict MDX coils!!!!!!!!!!!!!!

I have a couple 180tr 30rb 410a chillers with 8 compressors.
they only hold about 80lbs per circuit?????????????????

did you pull the charge and weigh it in???

sounds to me like it is over charged?

it only takes a couple ounces!!!!!!!!

Okay there are three points where the header attaches. Top middle and bottom. The two top most flanges are abnormally hot. The bottom most "suction" one was cold and sweating like it was a suction line. I'm going to check in the morning for that aluminum horizontal line.

[supertek65]

30rb wants 7.6* superheat.

11 is high

Well first I pulled 83 # of gas out. We had the coils replaced and recharged with 80 lbs because that's all we had at the time. There are four compressors and the problem is across all sets and if the coils are six feet across then two feet get warm and the remaining four stay cold. Walking on top of the unit, the right side farther away from the header is blowing cold while the header side blows warm/hot. It's almost like the refrigerant isn't making it across to the other side and only going in and out like the coil is "backwards". The display shows 11 degrees SH

[rscamaro]

30rb wants 7.6* superheat.

11 is high

Which would make it look to me like it was undercharged, unless there was a high load on the system.

Check the subcooling, as others have said, it doesn't take much to overcharge. There are 10 or so needle thin holes in each one of those horizontal runs across the length of the coil and a piece of dessicant will create havoc. If you are sweating, common sense tells me that you have a pressure drop,

...Ron