I am at a loss

[Airbag]

The AC guy came by with his equipment and we serviced the split AC. It did nothing but blow warm air. So we determined it had a high pressure side blockage. So out came the evap section and put it on the bench. Tried to blow through it and sure enough plugged solid. So being at a loss we back flushed it with acetone and compressed air until we thought we had good flow. Back in the bus it goes reservice the R-22 and the best we could get 87 degree air at the plenum. I don't know where to go from here short of just giving up and cut my losses. Any ideas? If I had it to do over I would buy new equipment.

The readings on the guages were 325 and 30 indicating still a blockage some where. It doesn't leak it just won't cool.

[jjrbus]

How many times have I shot myself in the foot saving a few pennys?  It seems the real talent to being cheap is to know when to cut my losses and move on.    Jim

[JohnEd]

Rick,

The orifice in the exp valve is so very tight that almost anything will plug it.  If you can remove the exp valve and replace it you might be able to clear the malfunction.  I don't think you can force enuf fluid thru the valve in a reverse flush to actually push the debris out.  I have always wondered why the filter dryer is located at the OP of the condenser......should be at the very input to the expansion Valve in the evap.

If you purchase a new evap alone you might cut your repair expense.   You know how you run those lines to the expan unit with the ends OFF.  This thread should put an end to that practice.  Can you fit a small filter into the line in front of the exp valve?  Just spit balling here.  They have gotten by without our doing that mod for a long long time, though.

The new super efficient units don't use R22 anymore. Also, they have variable and multi speed compressors that respond to load somehow.  The older R22 versions are cheaper but the new designs are much more efficient and that adds up to more BTU's for fewer amps.  A real plus in our arena, no?

John

[Nick Badame Refrig/ACC]

Hi Rick,

Just a thought, If you have any moisture in the system, [even a drop] it will freeze in the orfice/expantion valve immediately...

It sounds like your system is contaminated and needs to be flushed, filtered, and dehydrated by an expert.

Good Luck
Nick-

[Airbag]

Guys everything you said makes sense. I did run the lines with caps on them. But maybe I should have blown them out just to be sure. Day late and dollar short. We vacuumed the system for hours before servicing. I am going to pull the evap out this weekend and take it apart and check the screen. It is an orifice tube arrangement and will have to unsolder it to do it. If the condensor is plugged is it possible to read such high pressure on the liquid side when the service port is down stream from the condenser?

I am not going to do anything with it until this weekend, just going to work and making my aircraft parts, I am too discoraged right now to mess with it.

On another note I was surprised to find no service ports on my roof unit. I guess they are disposable? It is time for a new one anyway lots of rust up there. What brand do you guys recommend? Nick I can buy it from you if you like. Seems the least I can do for all the help and words of encouragement. Nick is there a new split system available now a days?