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  1. #14
    Join Date
    Jun 2003
    Location
    Virginia
    Posts
    376
    It sounds like there is a problem with your expansion valves but without more information (make, model, etc) and/or pictures, I'm not so sure we can help much...

  2. #15
    Join Date
    Mar 2010
    Posts
    8
    Quote Originally Posted by y7turbo View Post
    stop guessing and take your subcooling and superheat readings.

    We need this basic info to actually help you.
    Haven't taken them yet because if I add refrigerant my head just comes up and suction stays at 60

  3. #16
    Join Date
    Mar 2010
    Posts
    8

    Red face

    Quote Originally Posted by prorefco View Post
    It sounds like there is a problem with your expansion valves but without more information (make, model, etc) and/or pictures, I'm not so sure we can help much...
    Thanks! I appreciate all the help boys! I'll be back at it in the morning... Hpefully will make some progress. Sorry for the lack of info on the valves.

  4. #17
    Join Date
    Jul 2006
    Location
    Anytown USA
    Posts
    2,055
    Quote Originally Posted by Delta31 View Post
    Haven't taken them yet because if I add refrigerant my head just comes up and suction stays at 60

    dont matter what your pressures do when you add gas, you NEED to take sh and sc readings to find out what the refrigerant is actually doing inside the system.

    Are all your condenser fans on while your checking pressures?

  5. #18
    Join Date
    May 2008
    Location
    Myrtle Creek. Oregon
    Posts
    182
    is the unit fully charged? got to be fully charged before you can check SH properly.

  6. #19
    Join Date
    Sep 2004
    Location
    Oklahoma
    Posts
    83
    Is the line set the right size for the dual evaporators?

    Lane

  7. #20
    Join Date
    Jan 2010
    Posts
    6,075
    Was it in front of a distributor ?

  8. #21
    Join Date
    Jun 2008
    Location
    Long Island, NY
    Posts
    200
    Lennox doesnt have just 4 ton TXV's, they use a 3.5-5 and it's most likely a Parker. I have changed out ton's of these. My garage HP is going on it's 3rd valve in 3 years.
    I would take some more measurements and lean toward restriction in the TXV.

  9. #22

    process tubes and bulbs reversed

    I have just ran across a problem with a 15 ton Lennox split system 410-a system and was having major problems with the refrigerant circuit. I pulled vacuums, leak checked, and charged both circuits at the same time on start up so I did not notice issues until after unit was running and I could not get the pressures, sub-cool/ superheat correct on either circuit. What I found through carefull pressurizing / vacuuming each cicuit individually was that the process tubes and txv bulbs were connected to the wrong suction line inside the air-handler from the factory. The pressures would very slowly creep towards the same pressure. I would have one line set at 250 psi nitrogen and the other at 50 psi. after 1/2 hour the pressures were 180 across all 4 lines of both line sets.

    I called Lennox technical and was told they had no problems reported with any of the units. I told them what I thought was happening and He said all they could do was give me a new evap coil to replace it with. 15-ton air-handler in tiny area all walls need to come out and the bar needs to come out....NO DEAL.. Well we flipped the process (equalizer) tubes over to the correct suction manifold in the air-handler and re-mounted the txv bulbs to the other suction line. Pulled individuall vacuums and started up all is correct now.

  10. #23
    Join Date
    Feb 2007
    Location
    michigan
    Posts
    71
    Take the bulb and hold it in your hands, the TXV should start rockin and rollin. If it doesnt start there.

  11. #24
    Join Date
    Nov 2005
    Posts
    1,350
    I would start by making sure my charge was correct. On a new install I would have weighed in the charge by sizing for the line set and what not. With an out door temp in the low to mid 70's you should have no problem getting a SH and SC. If you had those readings you would know what was going on. I would suspect to see some sort of frost somewhere. Are the TXV's adjustable? If so, crank them open and see if you can get your suction to rise.
    I STARTED WITH NOTHING, AND I STILL HAVE MOST OF IT!

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