Results 1 to 11 of 11
  1. #1
    Join Date
    Aug 2010
    Location
    Wichita Fall, Tx
    Posts
    70

    TXV and Interal/External Equalizer

    I get how the bulb controls the valve and I understand the equalizer tube measures or you can say senses the evaporator pressure. But how does the spring at the bottom come into play?

    I'm a student and just starting to learn this stuff so go easy!

    1-Remote bulb pressure
    2-Evaporator pressure
    3-Superheat spring equivalent pressure???
    When they say "Superheat spring pressure" is this set at the warehouse and then adjusted in the field based on the techs reading? (This is what I'm assuming) Also, If I'm wrong on the equilizer tube please say so.

    Thanks

  2. #2
    Join Date
    Oct 2010
    Location
    SW Michigan, near Battle Creek
    Posts
    921
    yeah sounds like you got it. without the spring the thing would go for 0 superheat.
    the sprng biases the diahramn to close the valve for supeheat.

  3. #3
    Join Date
    Sep 2010
    Location
    Oregon
    Posts
    68
    Hmm, I've been out of trade school for awhile and so I know there's some things I've forgotten, but I always thought the equalizer tube was to equalize the system pressure after shut down. The reason I always thought it had the tube to equalize (or balance the system) was so that when the compressor starts up it's not trying to do so against a high head pressure; causing it to have trouble starting amongst other things. Maybe I'm misunderstanding the use of the term "equalizer tube" here because the tube the OP talks about sounds like the one that attaches to the bulb itself, and the one I'm describing is not that. However, the one I described (as far as I know) is called the "equalizer tube."

    Please correct me if I'm wrong.

  4. #4
    Join Date
    Aug 2006
    Location
    Wisconsin
    Posts
    1,504
    Quote Originally Posted by AP KING View Post
    Hmm, I've been out of trade school for awhile and so I know there's some things I've forgotten, but I always thought the equalizer tube was to equalize the system pressure after shut down. The reason I always thought it had the tube to equalize (or balance the system) was so that when the compressor starts up it's not trying to do so against a high head pressure; causing it to have trouble starting amongst other things. Maybe I'm misunderstanding the use of the term "equalizer tube" here because the tube the OP talks about sounds like the one that attaches to the bulb itself, and the one I'm describing is not that. However, the one I described (as far as I know) is called the "equalizer tube."

    Please correct me if I'm wrong.
    Your wrong. The external equalizer is a force that closes the valve as evaporator pressure increases.
    Buy American! The job you save may be your own.

  5. #5
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,770
    The equalizer line. Has been named a misleading name. Many people/techs think it equalizes the pressures after shut off. As stated above. It doesn't.

    It is a more accurate way to determine evap coil pressure, then using an internal(equalizer/sensing ability).

    Balanced port/hard shut off TXVs have external equalizers.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  6. #6
    Join Date
    Aug 2002
    Location
    Southold.calm
    Posts
    5,437
    Maybe this will clear it up.
    Attached Images Attached Images

  7. #7
    Join Date
    Aug 2010
    Location
    Wichita Fall, Tx
    Posts
    70
    Thanks! I've got a feeling there's going to be a pop quiz Tue. nobody in the class new the answer and he seemed a little disappointed. But I've done my home work and I'm lock and loaded with a answer.

  8. #8
    Join Date
    Sep 2010
    Location
    Oregon
    Posts
    68
    Quote Originally Posted by pecmsg View Post
    Maybe this will clear it up.
    Very good information, I'm always game for good info.. thanks for that. It seems the bleed port is what I was refering to, but I still had it wrong because it's not an actual copper tube that taps back into the suction line. I was definately picturing the equalizer line, but had it's function wrong. Thanks again for clearing that up.

  9. #9
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,418
    Quote Originally Posted by WFL-TX View Post
    I get how the bulb controls the valve and I understand the equalizer tube measures or you can say senses the evaporator pressure. But how does the spring at the bottom come into play?

    I'm a student and just starting to learn this stuff so go easy!

    1-Remote bulb pressure
    2-Evaporator pressure
    3-Superheat spring equivalent pressure???
    When they say "Superheat spring pressure" is this set at the warehouse and then adjusted in the field based on the techs reading? (This is what I'm assuming) Also, If I'm wrong on the equilizer tube please say so.

    Thanks
    Something to remember.

    TXVs are NOT preset to any real setting.

    The stem is wound a given number or turns, normally to midpoint, and called good.

    For proper operation, it MUST MUST MUST be set in the field.

    Installing a valve and not adjusting it is only doing half of the job.

  10. #10
    Join Date
    Aug 2002
    Location
    Southold.calm
    Posts
    5,437
    Quote Originally Posted by WFL-TX View Post
    Thanks! I've got a feeling there's going to be a pop quiz Tue. nobody in the class new the answer and he seemed a little disappointed. But I've done my home work and I'm lock and loaded with a answer.
    Quote Originally Posted by AP KING View Post
    Very good information, I'm always game for good info.. thanks for that. It seems the bleed port is what I was refering to, but I still had it wrong because it's not an actual copper tube that taps back into the suction line. I was definately picturing the equalizer line, but had it's function wrong. Thanks again for clearing that up.
    That’s what were here for.

    WFL-TX

    You can never have too much information.

    AP

    Keep Reading

    And listen to JP
    Attached Images Attached Images

  11. #11
    Join Date
    Sep 2004
    Location
    Kansas City, Kansas, United States
    Posts
    13,832
    the equalizer line EXTERNAL is actually a copper line that you have to install

    it compensates for the pressure drop across the coil!

    if you tap into the suction line upstream of the sensing bulb location???

    and the exv bleeds by??

    the sensing bulb will get a false reading!!!!!!!!!!1

    always tap in/install external equalizer down stream of the sensing bulb!!!!!1



    Quote Originally Posted by AP KING View Post
    Very good information, I'm always game for good info.. thanks for that. It seems the bleed port is what I was refering to, but I still had it wrong because it's not an actual copper tube that taps back into the suction line. I was definately picturing the equalizer line, but had it's function wrong. Thanks again for clearing that up.
    I WILL SELL WORK,GENERATE BUSINESS, GO GET NEW CUSTOMERS!
    YOU SHUT THE HELL UP AND QUIT RUNNING YOUR MOUTH!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event