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R1976
23-03-2009, 09:54 PM
Hi,

I ran a system today and had a suction pressure of 5 bar. I have never seen one so low on 410A and charged to manufacturers guidelines, there was frosting on suction valve and inlet/outlets to evap after a couple of minutes.

Acson A5LC25CR-ACPOC-R outdoor unit connected to AHU.

Superheat about 7K, air off evap 6K, ambient 13K.
HeathT
23-03-2009, 10:05 PM
Have you checked air flow off evap coil. are the filters and the coil both clean?
R1976
23-03-2009, 10:32 PM
Yes very clean, new unit.
Brian_UK
23-03-2009, 10:44 PM
What is the expansion device on the AHU, also is the AHU Acson as well?
R1976
23-03-2009, 10:57 PM
Capilary expansion device, no fan speed control, quite a simple unit with lives to outdoor fan and compressor from control panel.

AHU is different manufacturer with coil of 5.6kW duty with distributer with two lines coming out onto evap. Now I think about it the Acson outdoor unit has 8.1kW duty and no inverter.
Brian_UK
23-03-2009, 11:25 PM
Capilary expansion device, no fan speed control, quite a simple unit with lives to outdoor fan and compressor from control panel.

AHU is different manufacturer with coil of 5.6kW duty with distributer with two lines coming out onto evap. Now I think about it the Acson outdoor unit has 8.1kW duty and no inverter.
Could be a slight mis-match there methinks. ;)
R1976
23-03-2009, 11:34 PM
Yes, what conditions would you expect to see. I have never seen mismatched units before?
al
23-03-2009, 11:40 PM
if ahu is full fresh air then an ambient stat should be fitted to hold off the dx, air on at 13 and off at 6, no condenser fan speed control is asking for ice up:D

al
R1976
23-03-2009, 11:48 PM
Just checked technical manual and it says outdoor is 5.8kW:o, I'm going to bed.

The AHU has heat recovery and damper stat, I had to run it to commission system.
nike123
25-03-2009, 07:08 AM
Check fan rotation direction and flow.
krio
26-03-2009, 01:52 AM
A useful file (for comparison).:)