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  1. #1
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    high discharge pressure after replacing the new condenser for 30 gh carrier chiller.



    dear friends,

    Yet, I did not visit the site. I have been told on telephone. Chiller model:30gh100,carrier chiller. New condenser coil 15fpi/inner grooved tube was replaced. After commissioning discharge pressure is very high. Client (carrier) is not approved condenser replacement job .After more inspection, again replaced the plane tube condenser coil 18fpi/plain tube for circuit A only. Commissioned with 700micron vacuum and dupont suva refrigerant. Required gas charge as per catalogue 29kg for each circuit. But now not fully charged. Primary readings are below.SP=70/DP=340/LIQUID LINE PRESSURE=310/AIR ENTERING TEMP=40C/LIQUID LINE TEMP =49C/DISCHARGE LINE TEMP=96C.othor readings are not available. Tomorrow I will go to site and full reading update you. Have any comments…….
    Last edited by moideen; 24-07-2013 at 09:13 AM.



  2. #2
    moideen's Avatar
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    Re: high discharge pressure after replacing the new condenser for 30 gh carrier chill

    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.
    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.

  3. #3
    moideen's Avatar
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    Re: high discharge pressure after replacing the new condenser for 30 gh carrier chill

    anybody can say, how to design the lower td air condenser?what will be the specifications?can increase fin pitch or row?but it will affect the air way resistance and pressure drop in condenser.

  4. #4
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    Re: high discharge pressure after replacing the new condenser for 30 gh carrier chill

    and a 30psi pressure drop

  5. #5
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    Re: high discharge pressure after replacing the new condenser for 30 gh carrier chill

    Clarification : an 18fpi coil replaced by a 15fpi coil. If that is correct, coil is short of surface area. Which will directly effect discharge conditions. It will be more evident at high ambient temps.

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