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24-07-2013, 07:29 AM #1
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.
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26-07-2013, 03:34 AM #2
Re: high discharge pressure after replacing the new condenser for 30 gh carrier chill
My observationDate. 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
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.
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26-07-2013, 06:44 AM #3
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.
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29-09-2013, 11:15 AM #4
Re: high discharge pressure after replacing the new condenser for 30 gh carrier chill
and a 30psi pressure drop
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30-09-2013, 12:07 AM #5
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.