Page 1 of 2 12 LastLast
Results 1 to 13 of 15
  1. #1
    I had an earlier post about my compressor and condenser fan would sometimes not come on.

    An experienced tech looked at my evaporator coils in the attic and said that I needed to change out the entire evaporator.

    His reason is because the thermostatic control valve is sticking and needs to be replaced.

    Does this sound right?


  2. #2
    Join Date
    May 2006
    Location
    east central indiana
    Posts
    1,117
    That does not sound right. The TXV is replaceable independent of the coil.
    edit: The TXV also has nothing to do with the condenser fan not running. Except maybe if there were a pressure switch to cycle the fan. The TXV could keep the compressor from starting, if it is not equalizing quickly enough, or at all.

    [Edited by 4l530 on 08-29-2006 at 08:40 PM]

  3. #3
    Join Date
    Aug 2006
    Location
    High Point, NC
    Posts
    155
    How old is your system? Can the new coil be matched to your existing outdoor unit? Why not replace the TXV valve? TXV valves can be replaced and you keep the original matched coil to your existing outdoor unit. How old is the entire system? If it has some age, it might be better to think about an entire replacement. I would tend to want another opinion without giving the information about the previous findings. Is the existing coil matched to your outside unit?

  4. #4
    Join Date
    Nov 2005
    Posts
    1,350
    wow! that's a new one. the txv can be replaced and yes it could be your problem. if the valve is obstructed or stuck your head pressure could get so high your outdoor unit may trip on thermal. depanding on what safeties you have on your unit. if the indoor unit is too old it may need to be replaced, if it is not cost effective to replace the txv or indoor coil.

  5. #5
    Thanks for your responses.

    Bought the house new, so the entire unit is ~4.5 years old.

    The coil is an ADP coil and the outside units is YORK. Does it matter if it is not from the same manufacturer?

    Can the TXV be replaced without extracting and recharging the freon?

    The tech explained that the compressor and condenser fan would stop because the TXV is keeping freon from getting back to the compressor, which causes overheating.

    He also showed me on his gauge in the morning, suction pressure was 10 lbs, then he came back in the afternoon and suction pressure was normal at 80 lbs. Another reason he gave to support that it is TXV sticking at times.

    I may still get another opinion, per your recommendation.

  6. #6
    Join Date
    Jul 2003
    Location
    Los Angeles, California
    Posts
    184
    I read your previous post. Since your system is only 4 years old, a stuck TXV is no reason to replace the indoor coil. In your previous post, your pressures were 10 suction and 180 high. If the TXV were stuck closed, I would think the high side pressure would be much higher. I would have the TXV replaced and have the system pressure tested with nitrogen to make sure there are no leaks.

    [Edited by rclaoac on 08-29-2006 at 09:24 PM]

  7. #7
    Join Date
    Aug 2006
    Location
    High Point, NC
    Posts
    155
    ADP makes generic coils for a lot of different brand units. This is probably a match since they were put in at the same time. I see no reason to replace the entire coil unless it is less expensive than the repair. But I would want the new coil to match my system. I do not know if you can get another exact ADP coil. The exact coil might go quicker than the TXV valve and save money.
    Due to abnormal pressures I would recommend recovery of the refrigerant, new liquid line dryer, nitrogen charge to check for leaks, evacuation of system with micron gauge, new refrigerant.

  8. #8
    Join Date
    May 2006
    Location
    Philadelphia, PA
    Posts
    1,391
    Originally posted by rclaoac
    I read your previous post. Since your system is only 4 years old, a stuck TXV is no reason to replace the indoor coil. In your previous post, your pressures were 10 suction and 180 high. If the TXV were stuck closed, I would think the high side pressure would be much higher. I would have the TXV replaced and have the system pressure tested with nitrogen to make sure there are no leaks.

    [Edited by rclaoac on 08-29-2006 at 09:24 PM]
    Incorrect. A restriction will cause the head pressure to be low. Sounds like pressure was checked when the system was running (10 psi) and then when it was off (80 psi). Just a guess since I cannot see it.

  9. #9
    Join Date
    May 2006
    Location
    east central indiana
    Posts
    1,117
    Originally posted by acquestion

    Can the TXV be replaced without extracting and recharging the freon?

    The tech explained that the compressor and condenser fan would stop because the TXV is keeping freon from getting back to the compressor, which causes overheating.

    He also showed me on his gauge in the morning, suction pressure was 10 lbs, then he came back in the afternoon and suction pressure was normal at 80 lbs. Another reason he gave to support that it is TXV sticking at times.

    I may still get another opinion, per your recommendation.
    At 10psig the compressor is starving for some cool refrigerant vapor, so overheating here makes sense. I'm still not convinced that has any effect on whether the fan runs though.
    I'm also not sure about the TXV sticking 'at times'. In my experience once they're stuck, they're stuck. But there could be a restriction in there that blocks it occasionally. If the TXV is mounted external to the coilbox, I almost wonder if the sensing bulb is well mounted and insulated?
    You probably could re-use the refrigerant, but it would be wise to follow iheatncoolinnc 's recommendation on that. I also think you should get another opinion from another company before proceeding.

  10. #10
    Join Date
    May 2006
    Location
    east central indiana
    Posts
    1,117
    Originally posted by comfortdoc
    Sounds like pressure was checked when the system was running (10 psi) and then when it was off (80 psi). Just a guess since I cannot see it.
    Good point there. It could just be low on charge.

  11. #11
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    16,000
    I would also make "SURE" this coil does not have a 5-year warranty, if so I would pull the whole coil and warranty it and of course there would be a pretty good labor charge, but at least you would not have to buy the coil. I guess because I sell RUUD 99% of the time I am not up to date on a lot of coil warranties but I do know Goodman, Aspen and RUUD have 5-year warranties on there coils.
    __________________________________________________ _______________________
    “Experience is a hard teacher because she gives the test first, the lesson afterwards". - Vernon Law

    "Never let success go to your head, and never let failure go to your heart". - Unknown

  12. #12
    Join Date
    Mar 2006
    Location
    Loganville, Ga
    Posts
    197

  13. #13
    Join Date
    Jul 2006
    Location
    Lancaster,Ohio
    Posts
    464
    Originally posted by comfortdoc
    Originally posted by rclaoac
    I read your previous post. Since your system is only 4 years old, a stuck TXV is no reason to replace the indoor coil. In your previous post, your pressures were 10 suction and 180 high. If the TXV were stuck closed, I would think the high side pressure would be much higher. I would have the TXV replaced and have the system pressure tested with nitrogen to make sure there are no leaks.

    [Edited by rclaoac on 08-29-2006 at 09:24 PM]
    Incorrect. A restriction will cause the head pressure to be low. Sounds like pressure was checked when the system was running (10 psi) and then when it was off (80 psi). Just a guess since I cannot see it.
    >>>>>acquestion never gives a head pressure. He give the suction pressure twice, several hour apart. If the TXV is restricted it would cause low suction pressure. The compressor would flood the condenser with freon as it does on a pump down. The head pressure will rise. The fact the the suction pressure fluctuates indicates a moving solid, perhaps a dryer breaking up or improper brazing practices. Mrbillpro is right about the warranty, As a new homeowner I would insist on dumping the charge clean out system install filter dryers and use nitrogen in brazing and recharge.
    IcyFlame

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