Results 1 to 5 of 5

Hybrid View

  1. #1
    Join Date
    Apr 2008
    Location
    Mesquite(Dallas), TX
    Posts
    44

    York YCAV207EA low discharge superheat

    I have this unit tripping on low discharge superheat. I have verified sensors and pressure transducers are ok. We have changed flash tank level sensor because to old one was bad and. Ow this problem keeps showing up. I was having problems with the latest sensor put in late last year and have replaced it again with the latest and greatest version which I believe is the same as the last one changed, feed valves and drain valves work correctly in test mode and seem to be working ok when running. I suspect when Economizer is on we are dumping some liquid back on compressor and that the flash tank is to full and level senser is bad again. Was hoping someone who has run into this might have some ideas. Thanks for any input.

  2. #2
    Join Date
    Jul 2012
    Location
    Fountain, Co.
    Posts
    3
    Low discharge superheat usually originates from either an over charge of refrigerant or over charge of oil. Both will give you lower discharge temps. If liquid was carrying over through the econ. valve I would imagine the comp. wouldn't be a bit noisy, you might be able to verify that by watching your amp draw. If the level in the flash tank was at 85% or greater for I can't remember how long it will lockout on High Flash Tank Level. A JCI tech., one of the best in Colorado Springs, told me a few years ago that those Danfoss valves on the earlier models had a problem with the plunger mechonism screw loosen up and backing out. If this is the case the valves might appear to be working properly.

    Hopefully this might help out.

  3. #3
    Join Date
    Apr 2008
    Location
    Mesquite(Dallas), TX
    Posts
    44
    Refrigerant charge has been weighed in. Oil has never been added to machine which is about 4 yrs old. I replaced level sensor last Nov. because it was reading higher than it was and starving evap. After replacing sensor it ran ok for awhile then started tripping on low discharge superheat. The new sensor was reading lower than actual level by 30 plus %. The new sensor had a calibration button which I set when level half in glass. It seemed to run ok for awhile. We have since replaced the sensor again with what was supposed to be a newer generation but is still the same part. Manually feed and drain valves open and close properly. I suspect the Le el sensor is reading low allowing carry over through the Economizer. I have put one of the same generation sensors in a different chiller and also had to recalibrate it. It is working ok so it's hard to condemn sensor.

  4. #4
    Join Date
    Jul 2012
    Location
    Fountain, Co.
    Posts
    3
    Does this low discharge superheat only show up with the econ. sol. energized? If so pull the sol. and run to see if fault goes away. What is the level in the tank while in econ. If I remember right it should try maintain 30-35% level in tank. I do have notes on this in one of our manuals. Did you ever get that High Level fault? I still think that if you were getting carry over you would have this fault or a high amp draw.

  5. #5
    Join Date
    Oct 2006
    Location
    Central Texas
    Posts
    624
    Got some extra questions for you. Are the low discharge superheat trips, faults or lockouts? Is there a certain period of the day when you notice this? If your compressor runs unloaded for an extended period of time oil can collect near the discharge sensor. Giving lower than normal readings. You're positive the suction temp sensor is within 2* and the transducer is right on? What are your flows like? I had a building with YCIV's on them building under occupied primary secondary flows, We'd get lot's low suction and low discharge superheat trips. 35% is the setpoint for the fill valve. What positions are the fill and drain valves @ when it trips? What is the suction superheat the drain valve is maintaining? @ the time of the trip? Can you see a level in the tank siteglass?
    The last time I changed a level sensor, it was causing a low suction trips backing the fill valve down and opening the drain.
    Sic Semper Tyrannis.

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