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  1. #14
    Join Date
    Aug 2006
    Location
    ohio
    Posts
    257
    I don't know what tonnage it was doing but it was doing 10.2°

  2. #15
    Quote Originally Posted by michael26 View Post
    I don't know what tonnage it was doing but it was doing 10.2°
    gpm x delta t /24= tons. if your gpm was verified at 450 while doing 10.2deg your looking at 191t fully loaded with a 200t chiller. given you have 35% glycol your doing very good.

  3. #16
    Join Date
    Jun 2013
    Posts
    11
    Quote Originally Posted by traneguy123 View Post
    I wouldnt be too alarmed at your approach with 35%. i have several rtac's running the same approach with the same concentration, all is fine. just double check your design gpm to your actual gpm. your one issue of tripping you corrected by lowering sat temp trip point, that should have been done at start up. running 250 gpm originally seems quite low, unless the system is designed for low flow. what tonnage was the chiller putting out fully loaded?

    I have RTAC250 running with the approach so high +22 and up evap refrig temp 39.8 and lowering, refrig liquid level static on 0.3 no up no down, trane tech said that the sensor must be changed in order to open and close how has to be, any idea??
    Thank you in advance

  4. #17
    Join Date
    Jul 2007
    Location
    The Hot South
    Posts
    1,298
    Quote Originally Posted by ncctech View Post
    I have RTAC250 running with the approach so high +22 and up evap refrig temp 39.8 and lowering, refrig liquid level static on 0.3 no up no down, trane tech said that the sensor must be changed in order to open and close how has to be, any idea??
    Thank you in advance
    You should be starting your own thread instead of hijacking someone else's.

  5. #18
    Join Date
    Jun 2013
    Posts
    11
    Cond refrig Pressure 239.3 psia
    Sat cond refrig temp 138 F
    Evap refrig pressure 50.3 psia
    Sat evpa Refrig temp 39.8
    Evap Approach temp 21.2
    Refrig liquid level 0.3 (no up no down, static)
    In some point the unit stop by evap wtr flow (high approach temp)

  6. #19
    Join Date
    Jun 2013
    Posts
    11
    Quote Originally Posted by R123 View Post
    You should be starting your own thread instead of hijacking someone else's.
    Ohh

    since we are talking about the same, i believe that was a good sample it is no my idea hack anybody just share the same situation

  7. #20
    Quote Originally Posted by ncctech View Post
    Cond refrig Pressure 239.3 psia
    Sat cond refrig temp 138 F
    Evap refrig pressure 50.3 psia
    Sat evpa Refrig temp 39.8
    Evap Approach temp 21.2
    Refrig liquid level 0.3 (no up no down, static)
    In some point the unit stop by evap wtr flow (high approach temp)
    whats your ambient temp? your sat cond seems a little high. water or glycol? % glycol? compare your actual gpm to design gpm. check sensors for accuracy.

  8. #21
    Join Date
    Jul 2007
    Location
    The Hot South
    Posts
    1,298
    I would take a close look at your leaving water temp sensor and make sure it isn't reading high.

  9. #22
    Join Date
    Jun 2013
    Posts
    11
    Quote Originally Posted by traneguy123 View Post
    whats your ambient temp? your sat cond seems a little high. water or glycol? % glycol? compare your actual gpm to design gpm. check sensors for accuracy.
    The ambient temp is about 80 F now, it is water not glycol, The liquid level sensor is static no up or down (+0.3)

  10. #23
    Join Date
    Jun 2013
    Posts
    11
    Quote Originally Posted by R123 View Post
    I would take a close look at your leaving water temp sensor and make sure it isn't reading high.
    I set the unit to 49 F and the water is leaving about 59-60 F, may drop 5 to 6 degrees in 1/2 hr until the unit stop with the log evap wtr flow (high approach temp) about 35-36 F

  11. #24
    Join Date
    Jul 2007
    Location
    The Hot South
    Posts
    1,298
    Quote Originally Posted by ncctech View Post
    I set the unit to 49 F and the water is leaving about 59-60 F, may drop 5 to 6 degrees in 1/2 hr until the unit stop with the log evap wtr flow (high approach temp) about 35-36 F
    Okay......but that doesn't mean you checked the accuracy of the leaving water temp sensor......

  12. #25
    Join Date
    Jul 2007
    Location
    The Hot South
    Posts
    1,298
    Also, what's the EXV position running at full load? Whats your discharge superheat at full load? What happens to the liquid level when you pump it down? Which sensor did the Trane tech say needs to be replaced? Why are you doubting your Trane tech?

  13. #26
    Quote Originally Posted by ncctech View Post
    The ambient temp is about 80 F now, it is water not glycol, The liquid level sensor is static no up or down (+0.3)
    sounds like you have a couple problems. your saturated condenser temp is too high for 80 degree ambient. all your fans working? coils clean? bet your coils are dirty. need to check gpm through evap, quite possible a flow issue, maybe fouled tubes. is it a closed loop? any inhibitors or treatment in water? are your pressures and temps the same on both circuits? level sensor on both circuits steady? do a pumpdown on chiller and checked operation of level sensors, quick and easy to do.

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