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Thread: Pulsing in TXV

  1. #27
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    Quote Originally Posted by ch4man View Post
    20 posts and not once was superheat or subcooling, actual or target mentioned.

    so can you answer these...

    OAT
    SST
    suction line temp
    CST
    liquid line temp
    return DB
    return WB
    supply DB
    supply WB.
    Not yet.

  2. #28
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    Quote Originally Posted by RMSG01 View Post
    kinda falls under that, its been working for thirty or forty years this way thing, may not be perfect, but it has been working non the less, but it is now not and given the information at the beginning of this thread, I am sure I would have stopped and not worried about the Wet Bulb/ Dry Bulb at any of the areas, nor any other temps for that matter, until I get it back to flowing refrigerant correctly... Just my thought process and not really into over working myself and over billing my customers either for unnecessary work at the inopportune time. Get it running, then tweak it into perfection.
    Agreed, lol.

  3. #29
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    Quote Originally Posted by ch4man View Post
    RA wet bulb tells one how much load the evap/TXV has to deal with, RA dry bulb gives a great way of determining target low side pressure. OAT does the same for target high side pressure.

    the other readings are needed for SH/SC. just the kind of info we here would need to help with a diagnosis.

    taking these simple measurements does not take much time at all, hardly unnecessary work, in fact very necessary

    and that time is way cheaper than pulling a charge and weighing it back in
    So you're thinking that a high side well over the chart and suction pressure not rising could still be an issue of a low charge? I only had a few minutes the other day to take a look at it (and had to get on the road) so I admit this was a quick diagnostic. I'm fairly certain I'm dealing with a stuck TXV, but as I said...I'm all ears. Getting ready to take another look at it, going to see if I can get any pressure difference by adding heat and cold to the bulb. Any suggestions you guys have are definitely welcome.

  4. #30
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    Quote Originally Posted by buford View Post
    why not just recover the charge and weigh it against the label, plus line set?
    I'm thinking that if I recover I'm going to replace it, lol.

  5. #31
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    If you warm up the TXV's sensing bulb does the suction pressure increase and the SSH decrease?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  6. #32
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    Quote Originally Posted by Poodle Head Mikey View Post
    If you warm up the TXV's sensing bulb does the suction pressure increase and the SSH decrease?
    I'm getting ready to check that now. It's been a busy week.

  7. #33
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    Not sure if playing with TXV did anything or not, but removed it from inside and affixed to tube outside of unit. Added cold and hot and had about a 20lb shift (on suction), so that seems to be working at this point. I did find some oil on the distributor coming off TXV, so that's enough to lean towards replacement.

    Suction pressure was 65 when I unhooked with a superheat of 25, high side 305 with a subcool of 9. Indoor entering (dry bulb) 78-79 with supply air 63.

    I did find blower wheel in need of cleaning so not going to add anything until I clean that as well as the coils.

    Thanks for the input guys.

  8. #34
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    Quote Originally Posted by S.T.Ranger View Post
    Not sure if playing with TXV did anything or not, but removed it from inside and affixed to tube outside of unit. Added cold and hot and had about a 20lb shift (on suction), so that seems to be working at this point. I did find some oil on the distributor coming off TXV, so that's enough to lean towards replacement.

    Suction pressure was 65 when I unhooked with a superheat of 25, high side 305 with a subcool of 9. Indoor entering (dry bulb) 78-79 with supply air 63.

    I did find blower wheel in need of cleaning so not going to add anything until I clean that as well as the coils.

    Thanks for the input guys.
    Thanks for the update. Hope all goes well.

    Sent from my SM-G960U using Tapatalk

  9. #35
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    Quote Originally Posted by S.T.Ranger View Post
    So you're thinking that a high side well over the chart and suction pressure not rising could still be an issue of a low charge? .
    no, my issue with this diagnosis was the fact you stated the liquid line temp was colder than the OAT. usually the high side pressure is elevated for a short period of time with a restriction. it will settle down after a time because there is no heat to reject as it cannot pick up heat from a restricted evap.

    i was only stating in this thread that one gets good help when good info is given . i gave answers based on information given.. we're good
    my boss thinks its possible to repeal the laws of physics

  10. #36
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    Quote Originally Posted by RMSG01 View Post
    So if I am understanding you correctly, all of those temp measurements, or perhaps one of them may just have an effect on the low side at a 20 over temp on the high side and cause a no change condition on the low side when adding refrigerant to a 30 over high side charge? At this point, those are irrelevant and mean nothing till the problem is corrected. Mook at this point and not needed information.

    It only took 20 post to find a troll

    congratulations, your the first to call me a troll after over 2300 posts, 12 years on this site and over 3 decades in the business!

    i think I'll change my username to Trollman!


    ps see the post above
    my boss thinks its possible to repeal the laws of physics

  11. #37
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    Quote Originally Posted by S.T.Ranger View Post
    Not sure if playing with TXV did anything or not, but removed it from inside and affixed to tube outside of unit. Added cold and hot and had about a 20lb shift (on suction), so that seems to be working at this point. I did find some oil on the distributor coming off TXV, so that's enough to lean towards replacement.

    Suction pressure was 65 when I unhooked with a superheat of 25, high side 305 with a subcool of 9. Indoor entering (dry bulb) 78-79 with supply air 63.

    I did find blower wheel in need of cleaning so not going to add anything until I clean that as well as the coils.

    Thanks for the input guys.
    high side is 305 PSI, thats 132 deg SST by the forane P/T chart, how hot was it outside today?
    my boss thinks its possible to repeal the laws of physics

  12. #38
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    Quote Originally Posted by ch4man View Post
    congratulations, your the first to call me a troll after over 2300 posts, 12 years on this site and over 3 decades in the business!

    i think I'll change my username to Trollman!


    ps see the post above
    LOL I kinda like that name, trollman!, and it comes with a cool hairdo too! I think he had mis-spoke about the temp, perhaps you missed that reply. It's all good, I was just busting your chops a little, feel free to bust mine back.

    I just couldn't see checking all of the other things yet, I totally understand using that information to get a system running as perfect as it can get or if you have that system that's just not working like it should, but refrigerant flows like expected, etc. etc. By the way, I had a boss once that like yours, thought it was possible to repeal physics, if he thought it saved him money, and if you called him with a simple question like, getting a 2" filter to replace a 1" filter, or any question, he would always ask, what's your:

    OAT
    SST
    suction line temp
    CST
    liquid line temp
    return DB
    return WB
    supply DB
    supply WB.

    He ask that on everything, no matter what it was, maybe it just kinda reminded me of him and his lead-tech style of management. I noticed your time on here and the # of post and thought, why not post it anyway, see where it goes, kinda like old times sake, when we would bust our bosses chops when he would ask those questions.

    You should atleast add Trollman! to your sig line LOL

  13. #39
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    its all good RMS. the OP was truly lacking info for a long distance diagnosis, also i try to get our junior techs to stick to the basics and let them find their own shortcuts and ROT's.

    i really havent touched many R22 units recently as 410a has pretty much saturated the area. and a very long time ago i gave up on pressures in favor of saturation temps with respect to both ambients and line temps. to add to that in the quest to master psycrometrics the WB/DB thing became second nature.

    but that being said you and others are right.. on some units its really a waste of energy, as my mother once said " the more you play with sh_t the worse it stinks!"
    my boss thinks its possible to repeal the laws of physics

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