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Thread: Lennox

  1. #1
    Join Date
    Nov 2004
    Location
    Jonesboro, Arkansas
    Posts
    122
    Working on an old Lennox, have no model number or any labels left. The condenser is the type that has the fan on the side above the coil. Hooked the gauges up on low side and get nothing, compressor is running the lines are neither hot or cold. I do not think it has any refregerant in it at all, homeowner says they charge with freon last year twice. Anyway do not understand why no gauge pressure on low side. Started raining both cats and dogs. Going back tomorrow, would appreciate any ideas. Thanks

  2. #2
    Join Date
    May 2004
    Location
    new jersey
    Posts
    338
    unit's probaly dead flat

  3. #3
    Join Date
    Nov 2004
    Location
    Jonesboro, Arkansas
    Posts
    122
    Also tried to put some 22 in it and it would not take it.

  4. #4
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,370
    Originally posted by ac rookie
    Also tried to put some 22 in it and it would not take it.
    Some older Lennox condensers have king valves on them. You won't get any kind of pressure reading or be able to introduce refrigerant into the system if the suction king valve is backseated and you've connected your gauge hose there.

    Reason I say this is unless the compressor valves are bad, if you were actually connected to the system and it was flat on charge, the suction side would likely show a small vacuum on your manifold gauge with the compressor running.

    If you're not hooking up the high side gauge whenever you put gauges on a system, get out of that habit now when you're doing refrigerant side troubleshooting. It might be okay for a PM when you're trying to minimize refrigerant loss but for troubleshooting, you need both hoses on the system.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  5. #5
    Join Date
    Nov 2004
    Location
    Jonesboro, Arkansas
    Posts
    122
    Thanks Shophound, will do I go back tomorrow and will get both lines on. And also get aquainted with those king valves. Thanks again

  6. #6

    Arrow Service Valves

    Originally posted by ac rookie
    Thanks Shophound, will do I go back tomorrow and will get both lines on. And also get aquainted with those king valves. Thanks again
    I was thinking the same thing SHophound has already mentioned, check that your service valves are cracked open a little.
    AllTemp Heating & Cooling

  7. #7
    Join Date
    Nov 2001
    Posts
    1,874
    smac,
    He's actually better off to replace the unit itself.

    It's probably the vavles as mentioned,
    Or the compressor isn't running, but the fan is.
    And you think the compressors running.

    ie: a bad capacitor
    If you try to fail, and succeed.
    Which have you done ?



  8. #8
    Join Date
    Apr 2004
    Location
    Niantic, Illinois
    Posts
    545
    Anyone dumping a bunch of time and money into an old slabcoil condenser is grasping onto the old days. They are loud, inefficient, and ugly. If it's leaking replace the lines, evap, and condenser. Everyoine will win. I'm not a sell sell sell kind of guy but in this case it's called for.

  9. #9
    Join Date
    Jul 2002
    Location
    St Paul, Minnesota
    Posts
    3,468
    Last time I had one of these old units to resusitate the elderly homeowner offered to help by asking if there is anything he could do. With his wife looking on, I said,

    "Ya, if you go grab a couple of shovels, I'll help you bury this thing." Then I gave him some kind of inflated (maybe not really) estimate of how much it may cost to get it running if the compressor would run.

    His wife took him inside and then he came back out and said, "uh, we decided to replace it."

    Good choice, old man.

  10. #10
    Join Date
    Nov 2004
    Location
    Jonesboro, Arkansas
    Posts
    122
    Hey guys, thanks for all the input. The unit was total out of refrigerant, the low side was showing a vacuum. But the compressor was still working through it all. I know it needs replaced but some people would rather pay less now(even though paying less twice a year adds up quick) put freon in and when I left it was putting out 53 degree are out of the registers although the liquid line going in the indoor coil is frosting a little bit.

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