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R1976
12-07-2010, 11:11 PM
Evening all,

I am having teething problems with a 5 degree room:eek:.

I have Profoid Quietis WPH13C outdoor and Friga-Bohn TA2R8P evaporator with Alco TI(E) expansion valve and size 1 orifice. Room measures approx 4x5m.

System runs and runs but will only achieve 10 degrees. I have charged 3.5Kg of R404A and pipes are 1/2" and 3/8" about 8m long, sight glass is full.

I have observed the following:-

Suction pressure = 70psi
Liquid pressure = 250psi
Evap air on/off = 10/7 degrees
Condenser air on/off = 17/32 degrees
Liquid before expansion valve = 32 degrees
Pipe temp after expansion valve = 4 degrees
suction temp after evap = 3-7 degrees

As you can see the evaporating pressure seems high and there is not a great deal of difference across the evap. I have been medling with the expansion valve and it doesn't seem to help, although I was messing with it afew days before.

I am thinking the expansion valve is faulty, it is new so is this possible?

Am I barking up the wrong tree?

Any help appreciated, I have to get this room right.

lawrence1
13-07-2010, 12:18 AM
R1976,
I don't know the unit capacity but a no 1 alco orifice is anly rated at 1.85kw R404a,,,,far too small.Pie sizes also seems far too small for a room 4mx5m.i think you need a unit with at least 4kw @-5c.pipe size 3/8'' x 5/8''

frank
13-07-2010, 08:25 PM
The TR2 is rated at 7.97kW with a dt of 10K or 5.31kW with a dt of 8K. Your figures indicate a dt of 3K.

According to the Alco site, you should have a 004 size orifice for this application with the TI-E.

Your condensing unit is rated for medium temp applications. The WPH13ZC has a nominal cooling duty of 1.72kW @ -10C evaporating with a dt of 10K.

Seems like a duff selection of equipment to me.

R1976
14-07-2010, 10:27 PM
Thanks for your replies,

The system was designed by a consultant in cooperation with a supplier and I am sure I saw somewhere that the system design was 12Kw.

We have another almost identical room and system on this site and that unit goes down to about 6 degrees although it does take some time.

What do you think of the temperatures I have measured in the system.

mikeref
15-07-2010, 01:33 AM
You have the wrong size orifice but the question is... will the evaporator and condensing unit support the workload created by fitting a #4 orifice?

R1976
15-07-2010, 09:31 PM
Who knows,

If we have a 1-2Kw system then a size 1 or 2 orifice is okay. Perhaps the whole system is completely undersized?

mikeref
16-07-2010, 12:58 AM
If i were there i could tell you straight up if you had a too small unit however, measure compressor amps and compare to unit specs then pump it down and fit #2 orifice and check hi/lo pressures and compressor amps again. If unit pressures go balistic then its too small for the job

benijoseph
17-07-2010, 07:25 PM
Dear 1976,

U have not mention that how old is the unit
or unit is new one or ever it has worked satisfactly?

rgds.

littleyapper
22-07-2010, 10:24 PM
sorry dude my money is on duff selection...