unit needs resetting over and over?? - Page 7
Page 7 of 8 FirstFirst 12345678 LastLast
Results 79 to 91 of 98
  1. #79
    Join Date
    May 2010
    Location
    oklahoma
    Posts
    12
    ok thank you everybody who gave me advise! I found the problem it was going off on CLO. I jumpered and the contactors sucked in put my gauges on and wow high pressure. The hvac tech before me must have charged it beer can cold. I recoverd some refrig and put the correct charge on it. Now it runs fine. The unit conditions a kitchen and there is alot of heat load which may have been why the guy charged it like he did who knows. Being new to the facility I was told to only reset it and not givin the chance to take any time with it. Again thank you everybody you made me look good to the boss! Sorry I didnt post sooner. I had a major problem with a very big York chiller. I got it running seems something wasnt right in the programing. I am clueless on that unit but it's running. Good thing I have you guys as back up lol.

  2. #80
    Join Date
    May 2010
    Location
    oklahoma
    Posts
    12
    Oh thought I would clarify a few. When the unit first went off on my watch. I looked for a call for cooling had 24v to Y1 & Y2. Checked for 24v to relay, good. Checked for line voltage to contactor good. Also ohmed out the contactor coils, little to no resistance. I did check voltage to the contactor coil but after I pushed in the contactor. (Stupid of me) After seeing what time had to say and others I went back and when the unit went off again. I tested it as it sat. 24 to y 24 to relay. No voltage at compressor or outdoor fan contactor coil but voltage to indoor contactor coil. Good line voltage going to contactor. 24v goin to both CLO's but no voltage coming out. I tested voltage at the pressure switches but got nothing. I tested voltage to compressor 112 on each leg. I jumped 2 & 3 at the CLO and it fired up. Then I tested amps to compressor. around 15 amps. put the gauges on and 80 lo side 375 pisg. I had just cleaned both coils earlier. Fans on and good air flow.

  3. #81
    Join Date
    Nov 2004
    Location
    Auburn, AL, USA
    Posts
    597
    Quote Originally Posted by garytulsa View Post
    Oh thought I would clarify a few. When the unit first went off on my watch. I looked for a call for cooling had 24v to Y1 & Y2. Checked for 24v to relay, good. Checked for line voltage to contactor good. I did check voltage to the contactor coil but after I pushed in the contactor. (Stupid of me) After seeing what time had to say and others I went back and when the unit went off again. I tested it as it sat. 24 to y 24 to relay. No voltage at compressor or outdoor fan contactor coil but voltage to indoor contactor coil. Good line voltage going to contactor. 24v goin to both CLO's but no voltage coming out. I tested voltage to compressor 112 on each leg. I jumped 2 & 3 at the CLO and it fired up. Then I tested amps to compressor. around 15 amps. put the gauges on and 80 lo side 375 pisg. I had just cleaned both coils earlier. Fans on and good air flow.

    Where you said "Stupid of me" I would disagree. Then all of us would be "stupid"; especially me. I've never in over 45 years of service found any contactor safety devices that reset by manually engaging the contactor relay like these CLO's do. It stumped me for a while too.

    Smart of you to know something different was going on.
    Smart of you to to try to figure it out and not just walk away from it.
    Smart of you to seek an answer and ask others when you don't know yet.
    Smart of you to follow through the way you seem to have done here.

    Looks like you're doing fine now and will do well in the future.

    Also, are you what I would call "in-house maintenance" at the facility you mentioned? That is what I've been doing for the last 10 years.
    jt

  4. #82
    Join Date
    May 2010
    Location
    oklahoma
    Posts
    12
    Yes I am in house maintenance guy. I went to HVAC school worked for three differnt companys in install tryin to work my way to service. Then took a possition as heat and air guy on facility maintenance crew.

  5. #83
    Join Date
    Jan 2010
    Posts
    5,975
    [QUOTE=garytulsa;6670832 I tested it as it sat. 24 to y 24 to relay. No voltage at compressor or outdoor fan contactor coil but voltage to indoor contactor coil. Good line voltage going to contactor. 24v goin to both CLO's but no voltage coming out. I tested voltage at the pressure switches but got nothing. I tested voltage to compressor 112 on each leg. I jumped 2 & 3 at the CLO and it fired up. Then I tested amps to compressor. around 15 amps. put the gauges on and 80 lo side 375 pisg. I had just cleaned both coils earlier. Fans on and good air flow.[/QUOTE]

    Ok Gary,
    Looks like a win win situation for all parties involved.
    No voltage at comp. or fan contactor. But voltage to blower contactor because not part of the 2-CLO's. Makes sense so far. Voltage into both CLO's terminals #2 but not out to terminal #3. If you would have checked terminal X you would have found it there. When you checked voltage at the pressure switches of course none there because it has to come from terminal #3 which was open due to CLO. When you jumped 2 & 3 you bypassed the CLO and apparently the high pressure switch had reset to a lower pressure and it fired up. Sooooooooo when the system is operating and one of the two pressure switches opens it kills low voltage to the contactor removing power passing thru the magic CLO loop triggering the CLO to trip.
    Wow i hope i never forget this.
    Great thread Gary and thanks for following up. I hope we all learned something here.

  6. #84
    Join Date
    Jan 2006
    Location
    New Mexico
    Posts
    44
    Great you found the problem, it'll happen again so why don't you throw a delay on break relay in, and use the two wires from CLO. If it does happen again, then it will be automatically reset to what length you dial in.

  7. #85
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    17,734
    Gary-

    This is a common problem on these Carrier units.

    Carrier does not use a txv on this design. It's a set of orifices in the header manifold going into the evaporator. Typically, a PM visitor notices some frosting on the headers, and sees high superheat, if he looks at that value at all.

    In an attempt to lower the superheat to an acceptable level, or just get rid of the frosting, he adds refrigerant.

    The fix for these units is to recover the refrigerant and replace the clogged header. Of course, you first eliminate all other restrictions first, but I have found two of these in the past year on these 1990's vintage Carrier RTU's.

    Check back at some point and see if the readings, particularly the superheat, are still good.

    Nice job!!!
    Last edited by timebuilder; 05-15-2010 at 12:15 AM.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

    AOP Forum Rules:







  8. #86
    Join Date
    Apr 2010
    Posts
    21
    Gary'
    Thank you for all your hard work that's good job found the problem that's great men.

  9. #87
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
    Posts
    3,699
    Hey Timebuilder you might want to reread the first paragraph of your last post.
    UA 100

    It takes three people to do anything around here. Two do the work, one explains to the crowd of people who showed up when they seen smoke and flames.

  10. #88
    Join Date
    Sep 2006
    Location
    Independence mo
    Posts
    34
    How manny VA is your X-Former and how manny feet is your Tstat wire?

  11. #89
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    17,734
    Quote Originally Posted by thegoodlistener View Post
    Hey Timebuilder you might want to reread the first paragraph of your last post.
    I take it you are about to say that you have seen some of these with txv's. I have not.

    I see the txv's used on the shorter models with the recessed fans. I believe the older ones were the DR series.

    Was that what you were referring to? Or was it the use of "low" instead of "high?"

    Must be morning after propofol syndrome....
    Last edited by timebuilder; 05-15-2010 at 08:55 AM.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

    AOP Forum Rules:







  12. #90
    Join Date
    Jul 2009
    Location
    Connectitaxed
    Posts
    2,644
    Quote Originally Posted by timebuilder View Post
    Gary-

    This is a common problem on these Carrier units.

    Carrier does not use a txv on this design. It's a set of orifices in the header manifold going into the evaporator. Typically, a PM visitor notices some frosting on the headers, and sees high superheat, if he looks at that value at all.

    In an attempt to lower the superheat to an acceptable level, or just get rid of the frosting, he adds refrigerant.

    The fix for these units is to recover the refrigerant and replace the clogged header. Of course, you first eliminate all other restrictions first, but I have found two of these in the past year on these 1990's vintage Carrier RTU's.

    Check back at some point and see if the readings, particularly the superheat, are still good.

    Nice job!!!
    Timebuilder, You have not had any luck in blowing the clog out of the header? I have had quite a bit of success in doing that in the past.

  13. #91
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    17,734
    Quote Originally Posted by pdrake65 View Post
    Timebuilder, You have not had any luck in blowing the clog out of the header? I have had quite a bit of success in doing that in the past.
    We made a decision that this approach was going to give the most consistent positive result. In many cases, telling a customer that something "might" work is equivalent to saying it "will " work, in the mind of the customer. Then, after trying to blow it out, we "own" it until it works properly.

    This way, we quote, repair, and it's done.
    Last edited by timebuilder; 05-15-2010 at 11:04 AM.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

    AOP Forum Rules:







Page 7 of 8 FirstFirst 12345678 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