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  1. #1
    Join Date
    Feb 2008
    Location
    Dubai
    Posts
    102

    Confused carrier 30gh high discharge after condenser replaced.

    Dear friends,
    I have a question. How to check the capacity of a running air cooled condenser with using its running parameters?as we know to check the evaporator capacity like 4.5*cfm*air enthalpy difference.has any formula for air cooled condenser?because we recently replaced the condenser of a 100 ton capacity carrier air cooled chiller with same specifications.discharge pressure is going very high.system properly evacuate(650micron) before gas charging.chiller model carrier 30gh100.sp=75,dp=340,discharge line temp.96c,subcooling 7K.any advice/comments appreciated.
    [/SIZE]

  2. #2
    Join Date
    Jul 2013
    Location
    Houston Texas
    Posts
    46
    Just a couple of questions. Was the charge weighed in? What was the reason for replacing the coil to begin with?

  3. #3
    Join Date
    Feb 2008
    Location
    Dubai
    Posts
    102
    Quote Originally Posted by digger1980DG View Post
    Just a couple of questions. Was the charge weighed in? What was the reason for replacing the coil to begin with?
    existing condenser was very old and damaged.as per the catalouge 29kg per circuit.but charged only 25kg.

  4. #4
    Join Date
    Dec 2009
    Location
    TN & MS
    Posts
    62
    Would check for any possible restrictions.
    "The race is to the driven....not the swift."

  5. #5
    Join Date
    Feb 2008
    Location
    Dubai
    Posts
    102
    you mean air side restriction.sure,new coil there is no restriction. but condenser pressure drop from discharge port to liquid line shutt off valve 35 psig.

  6. #6
    Quote Originally Posted by moideen View Post
    you mean air side restriction.sure,new coil there is no restriction. but condenser pressure drop from discharge port to liquid line shutt off valve 35 psig.
    I have seen some replacement coils where the plastic end caps were shoved up inside the tubes so far you couldn't even see them and piping was reconnected without removing the obstruction. Also had one job where a two foot section of twine was found inside the piping at the condenser outlet.

  7. #7
    Join Date
    Jan 2005
    Location
    Houston TX
    Posts
    874
    Just a simple thought I gather during coil replacement did you have to remove any fans ? Are they all running in the correct rotation ? - GEO
    Once in a while everything falls into place and I am able to move forward, most of the time it just falls all over the place and I can't go anywhere-GEO

  8. #8
    Join Date
    Dec 2009
    Location
    TN & MS
    Posts
    62
    Airside or refrigerant side. We're filter driers replaced? Fans turning in proper rotation?
    "The race is to the driven....not the swift."

  9. #9
    Join Date
    Jun 2008
    Location
    Windsor, Ont.
    Posts
    490
    Quote Originally Posted by moideen View Post
    Dear friends,
    I have a question. How to check the capacity of a running air cooled condenser with using its running parameters?as we know to check the evaporator capacity like 4.5*cfm*air enthalpy difference.has any formula for air cooled condenser?because we recently replaced the condenser of a 100 ton capacity carrier air cooled chiller with same specifications.discharge pressure is going very high.system properly evacuate(650micron) before gas charging.chiller model carrier 30gh100.sp=75,dp=340,discharge line temp.96c,subcooling 7K.any advice/comments appreciated.
    [/SIZE]
    What refrigerant and just out of curiosity what is the ambient temperature noting that your location shows Dubai?? You say you replaced coil with same specifications, does that mean you bought the coil from OEM or had coil custom made from a different manufacturer??

  10. #10
    Join Date
    Feb 2008
    Location
    Dubai
    Posts
    102
    Date. Time
    Operating Parameters CIRCUIT - A CIRCUIT _ B
    Refrigerant R22
    Suction Pressure 65 psig
    Saturated suction Temperature. 3.1c
    Suction line Temperature. No avl
    Super Heat-compressor(REQUIRED 16C) 30c
    Discharge Pressure 330
    Saturated cond. Temperature. 57.5
    discharge line temp 92C.
    Liquid Line Temperature. 54.3
    Liquid line pressure 300
    Sub Cooling 1k
    Pressure drop in high side 25 psig
    EXV
    Ambient Temperature. 39c
    Condenser TD 18k
    Condenser approach/LTD 1K
    EVAPORATOR TD 10K
    Evaporator LTD/APPROACH 6k
    Condenser CFM as per catalogue 63199
    condenser avg.air veleocity 700FPM AND 529 FPM.
    condenser coil face area 30 FT2
    Condenser Air In Temperature. 39c
    Condenser Air Out Temperature. 56.3
    Condenser Air delta Temperature. 17.3c
    Chilled Water In Temperature. 13c
    Chilled Water Out Temperature. 9c
    chilled water Delta T 4k
    Chilled Water in Pressure 19psig
    Chilled Water Out Pressure 15psig
    Chilled Water delta Pressure 3psig
    Chilled water flow rate No avl
    Refrigerant Charge approximates 24 kg
    Refrigerant Charge as per catalogue 29kg.
    Average Volts 380
    System Sight Glass Slightly flashing at exv 100% open
    Avg. Amps Comp A1-06E299-CARLYLE 62 A
    Avg. Amps Comp A2-06E270-CARLYLE 62 A
    Avg. Amps Comp B1-06E299-CARLYLE 46A
    Avg. Amps Comp B2-06E270-CARLYLE 46 A
    My observation
    1. Condenser TD is high-so the condenser is undersized.(the condense manufactured as per the existing desighn,2 row coil)
    2. Condenser air delta T is high-but calculated cfm is matching to the catalogue cfm.
    3. Condenser approach is low=so the heat transfer takes place.
    4. Sub cooling is very low,as per catalogue minimum need 7k.
    5. Chilled water delta T is low, because only two compressors are working, B circuit is shut off.so to be maintained the delta T is 2.5c.
    I am again thinking,have you any comments.
    (find the attachment,put in pdf table)readings.pdf

  11. #11
    Join Date
    Jun 2011
    Location
    Detroit, MI
    Posts
    67
    Another basic, but potentially revealing check... if you are using the machine's pressure sensor, was the actual pressure verified with another instrument...say a set of gauges? I'm totally not trying to be a jerk, it's just that I know how tempting it is to rely on those fancy little electronic devices. Also, if I wanted to double check that I didn't get a big slug of air in the machine, I would pump it down (provided I could) and try and isolate the charge in the condenser. Then, run the cfm's for a few minutes then compare the sat temp in the condenser with ambient. I've had some read a touch high (2-3 deg) due to the heat from the compressor, but when there is a considerable amount of air in there, it will show right up with the sat temp higher than ambient. Just a couple simple things to check, hope it helps. I'm curious....what head pressure are you expecting? With an ambient of 103F and a leaving air temp of 133.4F and R22 that falls in line with the generalized 30F above ambient... and if that can be applied to this chiller, 330psi sounds fairly inline to me...wish I could find the IOM....what's the full model #?

  12. #12
    Join Date
    Feb 2008
    Location
    Dubai
    Posts
    102
    Quote Originally Posted by Cadrion View Post
    Another basic, but potentially revealing check... if you are using the machine's pressure sensor, was the actual pressure verified with another instrument...say a set of gauges? I'm totally not trying to be a jerk, it's just that I know how tempting it is to rely on those fancy little electronic devices. Also, if I wanted to double check that I didn't get a big slug of air in the machine, I would pump it down (provided I could) and try and isolate the charge in the condenser. Then, run the cfm's for a few minutes then compare the sat temp in the condenser with ambient. I've had some read a touch high (2-3 deg) due to the heat from the compressor, but when there is a considerable amount of air in there, it will show right up with the sat temp higher than ambient. Just a couple simple things to check, hope it helps. I'm curious....what head pressure are you expecting? With an ambient of 103F and a leaving air temp of 133.4F and R22 that falls in line with the generalized 30F above ambient... and if that can be applied to this chiller, 330psi sounds fairly inline to me...wish I could find the IOM....what's the full model #?
    Thanks your replay,my gauge reading and chiller display readings are same.i got the micron 650,and if there is air then the discharge temp.and sub cooling will go high.but these readings are low.now system is nor fully charged.when charging pressure elevating and may reach the td above 35f.
    For suggested td is for hot climate maximum 20f.next month dubai climate will reach to 118f.
    30gh100-015h-nee-a&b

  13. #13
    Join Date
    Feb 2008
    Location
    Dubai
    Posts
    102
    now i mainly suspect,the entering and leaving air of condenser difference is very high.sorry i forgot to say the history ,the new condenser is 2nd replacement.the first condenser also was same problem. that why manufacture increases 17fin/inch.the existing was 15fin/inch.

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