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judging by how much you have ad to clean the screen i would suggest changing the txv, changing compressor oil, LLFD, and replacing the refrigerant. then check superheat and how fast the box drops. i think you have some junk stuck inside the txv causing floodback. i would get this fixed before it washes out the bearings on the compressor

Zuke

As I said earlier "Something is wrong if u have 35 SH @ comp and that much ice on comp. wrong freon??? Bad gauges? Plugged suct filter?? "

I'm sure you are on the right track. Most suction filters have an inlet pressure tap. I care a lot more about pressure drop than temp drop. Unless you are flooding you will not have temp drop across a plugged suction filter. I think you will have to pinch your TXV way back after changing the Suct filter.

Thanks

MIke

The TXV sounds like it may be overfeeding. Since you said the screen was dirty, I'm guessing that in the past, somebody opened it up a little too much to compensate.

pulls down nicely everytime, suction drier has 6 deg difference across it, ices up to the beginning of drier and than ices the rest of the way later, changing both driers first and making sure coil ism free from ice, than going to check pressures again

Does it have a suction service valve you can front seat to see if it quickly pulls into a vacuum?

It has 404 in it cause I put it in, evap in and out is ten degrees diff, 19 and nine, melting the whole coil now and than going to recheck, has a suction drier on it, will check temp diff across as we'll, compressor pumps down nice, solenoid leaks back ever so slightly

One of the defrost heaters is broken so I am checking on trying to replace it on an old Hobart as well

Where are u measuring duct press? Comp model#. ?
Enter & leaving air temp at evap?

Do u know how to test to see what kind of freon?

Zuke

Something is wrong if u have 35 SH @ comp and that much ice on comp. wrong freon??? Bad gauges? Plugged suct filter??

I would verify correct charge before going any further. I reread the OP and 220 @ 80* ambient is low.

Superheat at compressor is 25-30
When unit is in defrost, compressor comes back on for split second off the pressure switch
Box never gets to zero now and it's mild out here now

I now have 13 psi at compressor, box temp is 15 deg, ice all the way back to compressor, half compressor iced up, evap iced over, just put it in defrost to melt off

It is rare, but something that has kicked my but a few times is a leak in the liquid to suction heat exchanger. I'm not sure I understand all of your symptoms. Could you re list them? Is your superheat at the comp 16 or 45? What is the box temp? If you could list all of the paramaters again, I would love to help.

Thanks
Mikd

update

Originally Posted by 2sac

A ZP powerhead is a necessary evil on low temp units with short linesets. The box takes forever to recover. Is the box located inside or outside the building? If outside, What's the ambient? Did you check for air infiltration? Did you do a pumpdown test? Is there adequate airflow around the coil?

It had been working great, the unit sits on top the cooler in a warehouse with the air being drawn from an outside window, it got 95 deg and they have no ventilation, ac in the back of the building and was hot, humid for over a week, than the freezer couldn't get to temp at all, it has since cooled down and i pumped it down, cleaned the txv screen which was black, flushed the screen with solvent and blew nitrogen thru liquid line to the disconnected txv, the airflow around the coil has plenty, just can't figure why the suction line is so cold now, got to believe the txv is not operating properly or has some gunk inside it messing it up. Is there anything I am missing!

A ZP powerhead is a necessary evil on low temp units with short linesets. The box takes forever to recover. Is the box located inside or outside the building? If outside, What's the ambient? Did you check for air infiltration? Did you do a pumpdown test? Is there adequate airflow around the coil?

Originally Posted by zuke19

What is zp mean

Pressure regulating.

Originally Posted by zuke19

superheat at compressor is 16 deg

Not good for that compressor. Manufactures want 20* min.

Originally Posted by 2sac

Does the powerhead have a ZP stamped on it?

What is zp mean

Originally Posted by zuke19

Did not check, the suction line temp is -13, the box did not drop in 3 hrs, the suction line temp is way too low for the temp in the box.

bulb has ice on it as well, superheat at compressor is 16 deg

I will have to check power head, I am going to change drier and txv, unless there are any other ideas out there

Originally Posted by Armon905

hello i see this was from yesterday just checking to see if this issue was taken care of or if your still in need of help

It still will not get to zero, have to go back tomorrow