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  1. #14
    Join Date
    Jan 2004
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    Lancaster PA
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    67,704
    TXV/TXVs sticking shut.
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    How many times must one fix something before it is fixed?

  2. #15
    Join Date
    Jun 2012
    Location
    Lynchburg, VA
    Posts
    22
    Interesting problem...

    Each circuit is totally independent with the exception that they share the same air (and fans) entering the condenser coil. So if we're dealing with an intermittent part failure, it is duplicated - rare, but not unheard of.

    Pressure Switch - verify the correct tripping pressure and not just what is stamped on the switch. 625 +/- 25 psig

    Condenser Fan Operation - it appears you have verified operation and witnessed a high-pressure fault, with the fans running (in correct rotation / blades secured). I'd thoroughly check and rule it out.

    Metering Device - I would think if there were a problem here, it would be trying to pump down, but you have also replaced them.

    Restricted Condenser Coil - bearing in mind that the circuits are independent it seems a far stretch that a plug was left in both of them at the factory (not impossible). I would think that if there were a plug, it would eventually find a spot in the coil to stay lodged and make the problem permanent. If there was a mfg defect, it would seem that the problem wouldn't be intermittent. Oil is a variable and it is possible that both compressors were overcharged with oil but I would think the oil would eventually interfere with the operation of the metering device.

    Compressor - again, anything in this part is happening to BOTH compressors and intermittent. Only thing I can think of would be sticking discharge valve, but I also believe it to be highly unlikely.

    I'm with timebuilder and would like to see some system readings when it is operating correctly. What are the compressor model numbers?

  3. #16
    Join Date
    Jun 2012
    Posts
    6

    Resolved York Predator ZF120

    Hello Spears Group,

    I'm sure you have resolved this problem by now as well and I appreciate your correspondence when this happened to me back in June.

    Better late than never: we found the problem with this York Predator a whior back after my posts and just wanted to add this for future information. The problem existed from the York factory. We found the liquid lines and evaporator lines switched between circuits. It wasn't so obvious at the time especially being newly manufactured and new condenser coils and such. This did make me wonder why York never got involved with the problem. Did this happen to a single unit or a whole run at the time of production. I'll never know.




    Quote Originally Posted by The Spears Group View Post
    We are experiencing the same issue with the ZF120. We have narrowed our symptoms down to: When 2nd stage satisfies, the head pressure for stage 1 goes up to near or over the cut out of 650 momentarily and then slowly drops back down. Tech support had us install a time delay to hold the HPS in the circuit till the head drops back down. We tried this but we are still getting sporadic nuissance trips. We jumped stage 2 with stage 1 for the time being till we can resolve the issue. I try to grasp everything I can with thoughts of possibly with this micro-channel coil....stage 2 runs it's course, coil heated up, aluminum micro-channel coil expands, then when it shuts down it cools off and contracts to original thickness, allowing more air through stage 2 coil that is not needed, making stage 1 coil (that is still running) only getting say 80% of the airflow required, in turn increasing the head pressure. Just a thought. I will let you know what our resolve is hopefully by days end.

  4. #17
    Join Date
    Aug 2012
    Location
    Palmyra, Missouri, United States
    Posts
    224
    sons of $@#!

  5. #18
    timebuilder's Avatar
    timebuilder is offline AOP Committee/Professional Member*
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    Nov 2006
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    Southeastern Pa
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    17,816
    I have seen an identical unit with the second stage on the bottom of the evap. Same situation, but this unit does not trip the pressure switches. That said, it WAS an installer cluster.

    I looked at the economizer, to make sure it has been set properly. Now, York puts a sticker on the enthalpy sensor, in big English letters, telling the installer to relocate the sensor to the fresh air hood.

    Now, if you don't speak English, that label means NOTHING.

    There is was, staring me right in the face, and impossible to miss.

    IF you speak English.

    So I finished the job our Home Depot laborer of the day did not, and I also corrected the baro damper, too.

    I'm getting sick of this nonsense. Get a bus and fill it, for heaven's sake, and get some Americans working.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

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  6. #19
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    Nov 2004
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    up in the hizzy
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    Quote Originally Posted by Hildy5652 View Post
    Hello Spears Group,

    I'm sure you have resolved this problem by now as well and I appreciate your correspondence when this happened to me back in June.

    Better late than never: we found the problem with this York Predator a whior back after my posts and just wanted to add this for future information. The problem existed from the York factory. We found the liquid lines and evaporator lines switched between circuits. It wasn't so obvious at the time especially being newly manufactured and new condenser coils and such. This did make me wonder why York never got involved with the problem. Did this happen to a single unit or a whole run at the time of production. I'll never know.
    was the liquid line from compressor "A" feeding evap. coil "B"?

  7. #20
    Join Date
    Aug 2012
    Location
    Tennessee
    Posts
    67
    I had on doing that a while back. It was a faulty limit switch losing 24vlts to condenser fan contactor. I could tech across and it would be fine, then push on my terminals and it would read open. Check your 24vlts and safety's

  8. #21
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    Nov 2004
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    up in the hizzy
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    1,375
    Quote Originally Posted by timebuilder View Post
    I have seen an identical unit with the second stage on the bottom of the evap. Same situation, but this unit does not trip the pressure switches. That said, it WAS an installer cluster.

    I looked at the economizer, to make sure it has been set properly. Now, York puts a sticker on the enthalpy sensor, in big English letters, telling the installer to relocate the sensor to the fresh air hood.

    Now, if you don't speak English, that label means NOTHING.

    There is was, staring me right in the face, and impossible to miss.

    IF you speak English.

    So I finished the job our Home Depot laborer of the day did not, and I also corrected the baro damper, too.

    I'm getting sick of this nonsense. Get a bus and fill it, for heaven's sake, and get some Americans working.
    I installed couple of predators a week ago, didn't see the "sticker with big English letters" but noticed the enthalpy sensors are now smaller,gray and made in Mexico.

  9. #22
    timebuilder's Avatar
    timebuilder is offline AOP Committee/Professional Member*
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    Quote Originally Posted by valdelocc View Post
    I installed couple of predators a week ago, didn't see the "sticker with big English letters" but noticed the enthalpy sensors are now smaller,gray and made in Mexico.

    That's right. If you order a repalcement enthalpy sensor for an older unit, you get the newer version. It looks like the photon torpedo casing from the Star Trek movies.

    Here is what I found. Maybe it should say, "reubicar a la campana de aire fresco."

    Name:  Senor was not relocated.JPG
Views: 171
Size:  115.1 KB
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

    AOP Forum Rules:







  10. #23
    Join Date
    May 2002
    Location
    evansville indiana
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    943
    Wow,
    mikeacman

  11. #24
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    Quote Originally Posted by timebuilder View Post
    That's right. If you order a repalcement enthalpy sensor for an older unit, you get the newer version. It looks like the photon torpedo casing from the Star Trek movies.

    Here is what I found. Maybe it should say, "reubicar a la campana de aire fresco."

    Name:  Senor was not relocated.JPG
Views: 171
Size:  115.1 KB
    that most be old inventory, the new ones came with the "photon torpedo" sensor, I dont believe it was made by Honeywell.

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