freezer low suction pressure

[eyresy]

Hi I have a copeland scroll condensing unit running a freezer coldroom, the unit gets down to -21c in no time and sight glass full with the occasional bubble . The only worry I have is the suction pressure is about 4-6psi which to me is too low. Liquid pressure is 200psi it has a new drier exp valve and orifice. So no blockages. Any info would be great
Alex

[frank]

Without knowing the refrigerant and suction pipe temperature we won't be able to comment

[eyresy]

Sorry frank its on 404a I haven't taken a suction pipe temp

[frank]

I've been working on a CO2 tank cooler today on 404a with a suction pressure of 5psig and a discharge pressure of 200 psig when I got there

Got the discharge pressure down to 105psig by deep cleaning the condenser then found that it was quite short of gas as the pipe temp was +7C.....didn't help that there was hardly any lagging on the pipe ...oh ...and discovered that it had an R22 TEV

Can you post a full set of system readings?

[NewmanRef]

I've been working on a CO2 tank cooler today on 404a with a suction pressure of 5psig and a discharge pressure of 200 psig when I got there

Got the discharge pressure down to 105psig by deep cleaning the condenser then found that it was quite short of gas as the pipe temp was +7C.....didn't help that there was hardly any lagging on the pipe ...oh ...and discovered that it had an R22 TEV

Can you post a full set of system readings?

You weren't at a nationwide bank in reading were you?

[eyresy]

Condensing unit about6 month old was on r22

[cadwaladr]

Check the txv,put a 404a valve on if it has not got one already and check bulb contact on outlet.

[frank]

You weren't at a nationwide bank in reading were you?

Do they have a 12tonne CO2 tank as well?

[eyresy]

The valve is 404a and I checked the bulb which was sat on top of tue pipe so I moved it to the side which helped a little. Im gonna change the valve tomorrow and see if that helps. Cheers frank

[monkey spanners]

Has it got the correct orifice in it? It would needed a bigger one than it had on R22.