Page 1 of 2 12 LastLast
Results 1 to 13 of 26

Thread: Scroll or TXV

  1. #1
    Join Date
    Jan 2010
    Posts
    6,232

    Scroll or TXV

    Lennox RTU M# GCS16-090-200-2Y
    #1 Compressor going straight into deep vacuum and high side sitting @ 100PSIG
    #1 circuit holds 6 pds. Added 2 pds with no change in high side pressure
    #1 circuit TXV frosted up as well as the distributor and cap tubes.
    Compressor pulling low amps. Shutting down on thermal overload.
    I'm thinking the compressor is not pumping but it sure is sucking
    Soooooooooo is it the compressor or a restricted TXV ?
    If restricted why not high head pressure ? Would it act as a pump down ( nothing in so nothing out ) Also how would a scroll compressor pump down but not pump ?
    What a DAY
    Guess I'm going back with both.

  2. #2
    Join Date
    Feb 2010
    Location
    In a boiler room
    Posts
    7,073
    You have compression ratio of 7 to 1, I doubt the compressor is the problem.

    It's not uncommon for high side pressure to be low when you have a liquid line or metering device restriction.

  3. #3
    Join Date
    Jan 2010
    Posts
    6,232
    Yes but I added 33% of the charge. Don't you think that would add some head pressure ? I even bleed some high side over to the low side and still no rise in head pressure. Also the compressor is getting hot at the top with no load and low head.

  4. #4
    Join Date
    Apr 2012
    Location
    lexington, NC
    Posts
    32
    Are you checking the head pressure at liquid port or discharge gas port?

  5. #5
    Join Date
    Feb 2010
    Location
    In a boiler room
    Posts
    7,073
    Quote Originally Posted by VTP99 View Post
    Yes but I added 33% of the charge. Don't you think that would add some head pressure ? I even bleed some high side over to the low side and still no rise in head pressure. Also the compressor is getting hot at the top with no load and low head.
    The top of the comp should get hot with no Refrigerant flow.

    I would replace the txv first if that is where the frost starts.

    Please don't replace both at once! Then we won't be any smarter!

  6. #6
    Join Date
    Dec 2011
    Location
    New Zealand
    Posts
    2,185
    Compressor is OK.
    It maybe as simple you do not have enough charge!
    and yes you could have a restriction, and it could be the TXV.
    Turn it on just for a few seconds, start to draw a low pressure. Turn off, does the pressure rise very slowly or fairly fast.

  7. #7
    Join Date
    Jan 2010
    Posts
    6,232
    Quote Originally Posted by Jpaulsmith View Post
    Are you checking the head pressure at liquid port or discharge gas port?
    Discharge gas port.

  8. #8
    Join Date
    Jan 2010
    Posts
    6,232
    Quote Originally Posted by chuckcrj View Post
    The top of the comp should get hot with no Refrigerant flow.

    I would replace the txv first if that is where the frost starts.

    Please don't replace both at once! Then we won't be any smarter!
    I here ya.....I would do the lesser of the two evils first. Actually I would lean towards the power element being dead.

  9. #9
    Join Date
    Jan 2010
    Posts
    6,232
    Quote Originally Posted by barbar View Post
    Compressor is OK.
    It maybe as simple you do not have enough charge!
    and yes you could have a restriction, and it could be the TXV.
    Turn it on just for a few seconds, start to draw a low pressure. Turn off, does the pressure rise very slowly or fairly fast.
    Hello down under ,
    Lived 9 months in New Zealand. Great country !

    Compressor goes right to a deep vac. When I shut it down
    it does rise faster then the #2 compressor.

  10. #10
    Join Date
    Apr 2012
    Location
    lexington, NC
    Posts
    32
    I think its odd that the head pressure doesn't rise over 100psi but stranger things have happen. TXV sounds like the fix, but what do I know I'm just a dumb noob to the site. lol

  11. #11
    Join Date
    Dec 2011
    Location
    New Zealand
    Posts
    2,185
    Quote Originally Posted by VTP99 View Post
    Hello down under ,
    Lived 9 months in New Zealand. Great country !

    Compressor goes right to a deep vac. When I shut it down
    it does rise faster then the #2 compressor.
    I hope you missed the shakes!

    I would suggest that you just need to add refrigerant.
    Your TXV is designed to pass liquid, and it is passing mainly vapour, with a tad of liquid, hence the heavy frost! And not enough refrigerant to fill the cond.

  12. #12
    Join Date
    Jan 2010
    Posts
    6,232
    [QUOTE=Jpaulsmith;13072801 but what do I know I'm just a dumb noob to the site. lol[/QUOTE]

    No such thing as a dumb noob (your a work in progress)

  13. #13
    Join Date
    Jan 2010
    Posts
    6,232
    Quote Originally Posted by barbar View Post
    I hope you missed the shakes!

    I would suggest that you just need to add refrigerant.
    Your TXV is designed to pass liquid, and it is passing mainly vapour, with a tad of liquid, hence the heavy frost! And not enough refrigerant to fill the cond.
    No shakes but lots of sheilas ! Spell check couldn't help me here. Loved that Wellington harbor. Both islands are beautiful and no crime a big plus

Page 1 of 2 12 LastLast

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