Charging walk in coolers and freezers

[thethomas4]

[QUOTE=AtoZhvac;4724222]Hi,


AtoZhvac
"Another thing say you are charging an R22 refrigeration system (large pan cooler) which requires 34 pounds of R-22. I had a heck of a time getting that much charged in. I ran warm water over the container many times to get the pressure back up to charge in the vapor."

It would not take long to charge 34lbs R-22 through liquid line

[thethomas4]

Pretty much just posting here so I get e-mail alerts when someone answers this question. I'm guessing it may be by closing the inlet service valve to the receiver and as system goes into pump-down the pressure drops in the receiver which allows you to add refrigerant?

Outlet of receiver. You need somewhere for the refrigerant to store

[tipsrfine]

Outlet of receiver. You need somewhere for the refrigerant to store

Should store in the condenser shouldn't it? since this is just the low ambient charge and the receiver is really just there to store the low ambient charge? I just do big refrigeration once in a blue moon.

[jpsmith1cm]

Outlet of receiver. You need somewhere for the refrigerant to store

Isn't that what the receiver does? Store refrigerant?

[thethomas4]

Isn't that what the receiver does? Store refrigerant?

absolutely

[tipsrfine]

Isn't that what the receiver does? Store refrigerant?

What I was meaning is that without low ambient conditions the additional refrigerant would not be needed. Sporlan's charging procedures first show you the proper charge of refrigerant needed without low ambient conditions. Under those conditions a receiver would not really be needed, so that charge should be able to be stored in the condenser in a pump-down. Next sporlan directs you to weigh in the additional refrigerant needed for low ambient conditions into the "high side";which is really why the receiver tank is there-to store the extra refrigerant needed for low ambient conditions. Therefore the normal charge should be able to be "stored" in the condenser at pump-down, alllowing you to weigh in the additional low ambient charge in the receiver that has been isolated from the condenser in a pump-down.

[jpsmith1cm]

Normally, I just charge into the suction line, as I said before.

[tipsrfine]

Normally, I just charge into the suction line, as I said before.

I understand what your saying. I was just hoping someone would answer the question about what spolan means by weighing in the charge on the high side. Being on a roof at 10 degrees when its snowing and windy at night and having to weigh in 10 lbs of refrigerant by "metering" it in on the low side can be hell. 10 lbs of liquid dumped in on the high side in a vaccume(?) would get you out of there in a minute.

[AtoZhvac]

Front seat the receiver king valve and let the compressor suck from the refrigerant tank.

Hi

Do you mean sucking in the R22 as liquid or vapor?

Thanks

[AtoZhvac]

What I was meaning is that without low ambient conditions the additional refrigerant would not be needed. Sporlan's charging procedures first show you the proper charge of refrigerant needed without low ambient conditions. Under those conditions a receiver would not really be needed, so that charge should be able to be stored in the condenser in a pump-down. Next sporlan directs you to weigh in the additional refrigerant needed for low ambient conditions into the "high side";which is really why the receiver tank is there-to store the extra refrigerant needed for low ambient conditions. Therefore the normal charge should be able to be "stored" in the condenser at pump-down, alllowing you to weigh in the additional low ambient charge in the receiver that has been isolated from the condenser in a pump-down.

Thanks for the reply please help me to understand a little better.
I was not aware that the condenser is isolated from the receiver in a pump down is this normal?

Thanks

[thethomas4]

Hi

Do you mean sucking in the R22 as liquid or vapor?

Thanks

Turn the can over and suck liquid from the liquid liquid line.

[tipsrfine]

Thanks for the reply please help me to understand a little better.
I was not aware that the condenser is isolated from the receiver in a pump down is this normal?

Thanks

No it is not. The receiver would have to have a service valve at the inlet that you could close to separate it from the high side. Just like a residential condensing unit. After that the unit will go into a pump-down just as when the liquid line solenoid valve closes when the unit is satisfied on temp. Except in this case you have stopped all liquid from entering the receiver, so the liquid has to be storred in the condenser-just like a residential pump down. This would place the receiver in a vacume.

[tipsrfine]

Turn the can over and suck liquid from the liquid liquid line.

Are you talking about just committing suicide and personally sucking that liquid refrigerant in or committing murder to the compressor by letting it suck straight liquid in? I'm guessing you mean metering in the liquid in to the suction line. Still, that can be time consumming.