View Full Version : high discharge pressure after replacing the new condenser for 30 gh carrier chiller.
moideen
24-07-2013, 07:29 AM
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…….
moideen
26-07-2013, 03:34 AM
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.
moideen
26-07-2013, 06:44 AM
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.
jason09
29-09-2013, 11:15 AM
and a 30psi pressure drop
Magoo
30-09-2013, 12:07 AM
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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