Replyhow good was the vacuum you pulled on it?Originally Posted by red949597
Regular Guest
Hi Guys This Is My First Post So Please Bare With Me. I Was On A Roof Top Unit Today And Had To Change Out The Compressor. Did The Normal New Drier, Suction Line Filter, Contactor. Nitro And Evac. Weighted In The Charge 11 Lbs R-22. Here Is Were It Gets Interesting, Started Up And Imediantly 10 Lbs Suction 200 Head. Shut Down Tried Agian Several Times Best Suction Was 22. Ok Observed A Frost Line From Outlet Side Of Suction Line Filter Through The Accumulater To Compressor. Since The System Was Monkeyed With Before Went Ahead And Changed The Suction Filter Again. Recharged, Same Problem. This System Has Fixed Tubes At The Evap Could They Be Stopped Up? Can A Accumulater Stop Up? What Am I Missing. Any Help Greatly Apreciated.
(forgot I Tried It In Heat Mode Same Problem)
Professional Member*
how good was the vacuum you pulled on it?
Banned
maybe the compressor that was changed was not bad!
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Regular Guest
first compressor was grounded on all three legs. have acid away in place.
Regular Guest
one hour vacum, nitrogen to 250, held fine, one hour vacum weighed in charge 11 lbs.
Regular Guest
I know you typed fixed tubes, but can you take the distrubitor apart if it contains a piston, I changed a compressor on a old York 5 ton rtu unit 7 month sago and the same problem, Since the compressor was lock up and had a leak, no refirgerant in the system, I removed the old compressor, installed the new compressor, and replaced the liquid line drier, evacuated the system, weighed the charge it 10.5lbs, and the same thing happend to me, recovered the refrigerant, took the metering device apart and found that the metering device/piston had debri blocking it, removed debri, and it ran like a champ.
Regular Guest
it has a header with short tubes between it and the evap coil. i am assuming this is where the metering devices are. looks like about five pairs. but i do not have any sweat?frost at these locations? all of the lines are dry?
Professional Member
purchase a new metering header assy.
Regular Guest
suction line drier? does it have access valves on both sides and if so I guess you check pressure drop. and this might sound crazy, and by no means judging your abilities but is suction line drier between the compressor and revering valve?
Regular Guest
as in a question to purchase a header assembly?
My misunderstanding I overlooked the part where you said it was a Heatpump, and that you tried it in heat and the same thing, pressure of 200 was it the discharge off the compressor or the liquid line pressure?
Regular Guest
suction line filter is between rsv and acumulater before compressor. hard to check as acess to filter is limited. i can see frost on the outlet side of the suction filter, same as first filter so i would be thinking filter clogged. but that quick. havent run unit for more than a few minutes.
Regular Guest
200 head at the compressor then went to 160 right before i shut it off
Regular Guest
Suction line drier, pancake type or one of the large ones, and you typed that the suction pressure dropped at start up, not after a short time of running, Was the compressor a burn out or just grounded, if it was a burn out I would guess sluge in the liquid line drier but it happens in heat also, rules out liquid line drier stopped up, it would not be that quick, I would remove the suction line drier, and then try it, Suction line drier used only for a short time frame any way, use your best judgment on using one, I use them only after a burn out or I suspect acid in the system, and no matter what I remove them after 2 days if possible. If you are going to remove the suction line drier add an access valve on the suction line at the evaporator so you can check suction pressure there in the cooling mode, may help in future trouble shooting and make it easier for yourself in the future.
Regular Guest
has a large one, right now. i do suspect a burn thats why filter and acid away. i guess it must have stopped up the tubes and got the other compressor. i think im going to try blowing her out again in the morn. if no luck there, will price header assembly.
Regular Guest
Don't know the size of the unit, and don't know if you have replaced a header but, it is much easier to replace the evaporator coil if it is found to be clogged tubes, once again it happens in heating, and should clear out and trap in the liquid line drier, when the heat was cycled, Had a clogged header on a 3.5 carrier 6years ago when I changed a compressor, but it was ac only, Changed 2 headers in 2 seperate carrier units, back when carrier first came out with metering devices crimped in the header and I swore never to replace another header again. The ones I changed the pistons where not crimped tightly from the factory and they came out
Professional Member*
One hour vacuum??? Thats a good reading to you huh?
Call the manufacturer and tell them that.
Professional Member*
When you noticed the temperature change or frost line at the suction drier, you most likely located the restriction.
Let us all know how you come out.
God Bless our Veterans
God Bless the USA
Professional Member*
When you tried it in heat mode were you still taking the suction pressure close to the compressor?
also put a drier in with a access port on it so you can take pressures on either side of it.
What does the evap coil/filter/blower wheel look like, and crazy question. ARe you SURE the fan was running???? If so where the amps close to FLA?
Professional Member
You say you pulled a one hour vacuum? Did you have a micron gauge on it?
Sounds like you have moisture in the system freezing up and causing a restriction. Purge with nitro, then pull another vac. using a micron gauge.
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