Freezing room problem

[TheUnknownw]

Greetings,

I have a cold room at -18 degrees C that does not go bellow -11. Refrigerant R404a.
At first it had a leak that i fixed but now it does not go bellow -11. It goes to -4 quickly and after that slowly until around -11. Defrost at 4 hours, it doesnt get clogged with ice because there aint much humidity (products are sealed in packages).
Condenser its not clogged either i cleaned it.
Evaporator has 2 fans and its kinda too big for the actual room which its around 2.5x2x2.1m
On the low side it has 2.5bars and the evaporating temperature after condenser its 30-35 degrees C.
It freezes on return line almost before the compressor and it does not have a liquid separator on the low side.
Any advice will be of much help.

Thank you in advance.

[Tayters]

2.5 bar means you are evaporating at -16°C, should be more like -30, around 1 bar.
Was it working before? Air/ non condensables mixed with the refrigerant? TEV been mucked about with?

[TheUnknownw]

True. But at 1 bar not even half of the evaporator is freezing so it doesnt even go under 0 degrees C.
There is no air or other gasses inside. I vacummed the system to -0.95 bar.
The owners says it worked before but from my point of view its kinda impossible.
I also believe that the TEV has been modified or the orrifice its too big, but it makes me wonder how it worked before.
I believe the next step is to removed the TEV check the nozzle and replace it if its too big right?

[cadwaladr]

You did chsrge it in liquid state i presume

[Tayters]

Perhaps the compressor isn't pumping properly. Might be worth doing a pump down test before looking at the TEV.

[cadwaladr]

Ok can we have some model numbers of evaporator and condensing unit,what is the delivery pressure and temperature going over the condensor please

[TheUnknownw]

Yes i charged liquid.
I will go there again tomorrow and check compressor model, check high pressure and evaporator model( which i think i wont find since its kinda old).
Thank you for info for now. I will b
Return with more info.

[cadwaladr]

In an average ambient,delivery pressure should be around250 psi,do checks on the compressor pump down the liquid to see if it achieves a vacuum,

[frank]

Symptoms of overcharge