Very high suction pressure r404a

[kencra34]

Hi all just wondering if you could help me, i have a salad unit with a one year old condensing unit (3/4).I service it last week and found the suction pressure up 90psi and liquid line 225psi (no discharge port).Firstly pumped system down to find compressor very sluggish bring system down on vacuum so rang supplier and they said leaking valves so they sent down new compressor, happy dayz so i thought, fitted new motor to find suction pressure up at 80psi and the liquid line 200psi but sight glass only showing very little in it, this system has 2 evaporators fan assisted but temperature very very slow to come down, but not by much over all, there is a new filter line drier fitted and checked both EXP valves and orfices checked out ok ,Has anybody any suggestions please?;)

[The Viking]

Time to get your thermometer out me finks...

What is the ambient temperature? Subcooling? Superheat?

:cool:

[kencra34]

Thank you for you reply the temps are as follows the Ambient is 21 degrees , discharge at compressor is 51 degrees and 53 degrees at condenser, liquid line at condenser is 31 degrees , evaporator exp valve liquid line is 27 degrees and suction 5 degrees and 11 degrees at bulb also the suction at compressor is 17 degrees , now the system is low on refrigerant but because of the high suction pressure of 80 psi i don't want to stress the suction valves with to high of pressure, also to just add is its a well salad unit with dual coldroom evaporators also the pressures are still the same , 80psi suction and 200 psi liquid line receiver pressure, Thank you for your time again ;)

[kencra34]

Sorry for the delay and forgot to add the system is running at 8 degrees.

[monkey spanners]

What was the original problem?

Defrost heaters stuck on?

If its a medium temp compressor it should cope with an evaporating temperature of 15C so i wouldn't be concerned with the suction pressure causing damage.

[kencra34]

Just was not reaching temp we did have leaking suction valve with the old compressor ( still under warranty ) and would not pull a full vacuum , so i fitted a replacement compressor, this system works with a off cycle defrost , if i keep putting gas in to fill the sight glass i'm sure the suction pressure would be nearly 100 psi :) , but over all its just not reaching temp 7 - 8 degrees is the lowest it gets :(

[monkey spanners]

I wouldn't worry at a 100psi suction if it is pulling the temperature down, if its a HBP compressor thats rated for +15C to -15C evaporating temperatures it is designed to cope with suction pressures in the range of 122psi to 38psi if its R404A. Running undercharged with high superheats would probably do more harm.

How much refrigerant did you take out originally and how much did you put back?