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weird one

Paul Fredricks_3
Paul Fredricks_3 Member Posts: 1,557
in A-C, Heat Pumps & Refrigeration
Went to a call with a tech the other day. Trane 2 1/2 ton, about 10 years old. Customer said that one never really worked right.Tech was getting weird pressures, tried to add a bit of refrigerant and the high side went to 350 (r-22). I started it up, reading 350 high, 22 low. Figured we'd start over, so we recovered the charge. Took 13 lbs out of a system whose factory charge was 4 lbs, 4 oz. Just a bit over charged.

Weighed the charge back in and started it up. Still strange pressures, 140 high, 20 low. And on start up the suction line startes freezing and then slowly warms.  Acting like a restriction, so I pump the unit down, climb up in the attic and pull the piston apart. All looks fine. Had my tech crack the high side valve for a second and that seemed fine. Put it back together, opened the valves, started it up, and everything is great. Pressures look good, temps are great!

All I can figure is that the high side valve was hanging up internally, or maybe the piston wasn't seated right. Running like a champ when we left.

Comments

  • Empire_2
    Empire_2 Member Posts: 2,340
    Hi Paul

    I understand the suction line was freezing after weigh in, but where exactly?  I remember back when strainer screens were in line with the piston.  Not saying this is the problem, but the only time I ran into this scenario was when I found an unidentified piece of Stuff just before piston in LL.  If you do check again cut back about a foot and take a look.  The thing I removed was loose and able to move back and forth.  I'd be interested to see what you find. 



    Mike T.
  • don_9
    don_9 Member Posts: 395
    edited July 2012
    PISTON

    It may have been that way for along time, trash in the piston.Many time guys will not check superheat nor subcool to know where the refrigerant is at in the system.so they are still stuck on what they have learn from other beer can cold baby.

    If the piston were not seating properly you would have high suction and low head in the cooling mode.unless someone came before you and overcharge it.
  • Paul Fredricks_3
    Paul Fredricks_3 Member Posts: 1,557
    update

    Unit is running fine. I get the feeling it was an issue with the high side valve. No problems since.
This discussion has been closed.

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