Walk in freezer 404a problem

[marter]

New Job. Its on of the stores ill be responsible for, anyway call came in walk in freezer at 20 degs, been at that temp all day, say it was fine before today

So I get there, verify its running, has a full sight glass, hook up gauges, 50/300, head pressure high, so i clean the coil, no change. Recover some gas (2 pounds) till i started to get bubbles in glass. head pressure still around 300.

its about 98deg ambient outside. 10deg. subcooling, let unit run for 30mins no change in box temp. Run water over condenser to get the head pressure down.
Pressure start looking better, 30/225 box cools down to 0deg, before i left.

Its got a alco style txv, this is what the other tech and I came up with a likely problem, the txv isn't feeding the coil right, and getting alot of liquid coming back up. Or there is a chance it could have some moisture in the system.

im not a full time refer guy

[rayr]

Low side seems kind of high at 50 for a bad valve. Did you take the bulb off and warm it in hand and watch pressure?
What was the SH at the evap. SH is more importand than SC in refrigeration.

[dangpgt97]

Couple things I see... The 300psi head looks about normal for a 98* day. The suction pressure is high for a 20* box. It's hard to say what exactly is going on there. If the txv wasn't feeding or the screen was plugged you would have low suction pressure and lower than normal head pressure. This all doesn't make a lot of sense to me.

Is this a new store? Is this the first time it's ran in this hot of weather?

[marter]

Low side seems kind of high at 50 for a bad valve. Did you take the bulb off and warm it in hand and watch pressure?
What was the SH at the evap. SH is more importand than SC in refrigeration.

didnt take it off, but it was mounted right and well insulated, at 50psi thats 15deg, but when it dropped down to 20psi when it was water cooled 20psi is -10below so thats a good pressure for a 0degree box

[jpsmith1cm]

Torch the receiver.

[marter]

Torch the receiver.

and what would this do, by heating up the receiver, that would boil more of the liquid to a vapor ? wouldn't that starve the txv more im confused

[VTP99]

The recever has a dip tube that goes to the bottom to pick up liquid only. By torching the recever you will see how much liquid is in there. Should be no more then 80% when it's pumped down.

[marter]

The recever has a dip tube that goes to the bottom to pick up liquid only. By torching the recever you will see how much liquid is in there. Should be no more then 80% when it's pumped down.

if its got a dip tube even if the receiver is all the way full of liquid its still going to pick up whats at the bottom though right, the liquid which is more dense would always be at the bottom

[dangpgt97]

I don't understand why torch the reciever? With a 98* ambient 300psi would give you a condensing temp of about 118* with 404a. He said he had a full sight glass.

[VTP99]

if its got a dip tube even if the receiver is all the way full of liquid its still going to pick up whats at the bottom though right, the liquid which is more dense would always be at the bottom

Yes the liquid is at the bottom. Now if the recever is full it would backup into the condenser which would increase your head pressure. If the dip tube is broken off above the liquid it will feed vapor.

[marter]

Yes the liquid is at the bottom. Now if the recever is full it would backup into the condenser which would increase your head pressure. If the dip tube is broken off above the liquid it will feed vapor.

that makes sense, i see the light ... ahhhh so purty
but by recovering some gas until i dont have a full sight glass, then im ensuring that the reviever is also not overfilled with liquid though, right

[dangpgt97]

that makes sense, i see the light ... ahhhh so purty
but by recovering some gas until i dont have a full sight glass, then im ensuring that the reviever is also not overfilled with liquid though, right

What condensing pressure/temperature would you expect to see with a 98* ambient and a warm box?

[marter]

What condensing pressure/temperature would you expect to see with a 98* ambient and a warm box?

110*/270psi