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View Full Version : How much 404A is in this thing?

man from trane
06-22-2009, 09:20 AM
I've got a 10-fan (2 X 5) Bohn air-cooled condenser on a split rack. Coils are 4-row, I think. About 150 HP of compressors. The nameplate is illegible. I'm going to have to replace the entire condenser within the next year and it serves the entire store. I'm trying to figure out how long everything will be down.

What I need to know is about how many lbs. of 404A is left in the condenser after I pump the rack down and close the ball valves at the rack going to the condenser. I've got about 15' of 2 5/8" piping to deal with, plus what's in the coils. What do you normally use to recover this amount of gas? My portable reclaimer isn't going to cut it. :eek: Hope the guy from the EPA has the day off...:D

jpsmith1cm
06-22-2009, 09:33 AM
See the Sporlan bulletin on headmaster controls. There is a way to calculate the amount of gas in the coil.

90-30-1 I think it is.

icemeister
06-22-2009, 10:09 AM
The current "BN" series condensers with 10 fans are shown as having a normal summer operating charge of either 125 or 140 lbs R404A, depending on the specific model.

http://www.heatcraftrpd.com/resources/prodbullet/BN-ACCTB0207.pdf
(See p.26)

(Some of the older design 10 fan unit info indicates 86 lbs.)
http://www.thecoldstandard.com/products/overview.asp?pid=44

You may be able to determine which you have by the pictures.

Phase Loss
06-22-2009, 10:16 AM
pull a torpedo recovery tank into a vacuum and let it sit in the freezer.

then pump the liquid out of the condenser by raising the head pressure. once the liquid is out of the condenser, only vapor will exist.

hook up the nice cold recovery tank that's holding a vacuum and let it suck out the vapor. anything left is de minimis :p

man from trane
06-22-2009, 11:12 AM
pull a torpedo recovery tank into a vacuum and let it sit in the freezer.

then pump the liquid out of the condenser by raising the head pressure. once the liquid is out of the condenser, only vapor will exist.

hook up the nice cold recovery tank that's holding a vacuum and let it suck out the vapor. anything left is de minimis :p

I like that idea! So, basically just shut off the fans during the system pumpdown to raise the head pressure and that should pretty much empty out the coils? Then I can isolate it before it cools down.

mccool
06-23-2009, 01:15 AM
Probably not needed in your area but if equipped, be sure to manually override the holdback valve and shut off receiver bypass. On a KG rack you can drop the condenser pressure very low by putting multiple KG systems into defrost as a last step after compressors are shut off, have drained condensers to very low pressures that way.

Phase Loss
06-23-2009, 06:22 AM
I like that idea! So, basically just shut off the fans during the system pumpdown to raise the head pressure and that should pretty much empty out the coils? Then I can isolate it before it cools down.

yup, more or less that is the basic idea.

I do not know the size of your evaporators...but when ever i pump out a condenser in a supermarket i usually pump a large line up down to 0# or a slight vacuum. then pump the liquid out of the condenser by raising the head pressure with the fan/pump off. once the pressure equals around 130* SCT that pretty much means the liquid is gone and only vapor exist. then i isolate the condenser and hook a hose up from the isolated condenser to the isolated line up that is at 0# and let the line up suck the high pressure vapor out of the condenser...only because i hate recovery tanks.

or if you have a running system with the same flavor...you are golden, because you can use that compressor to pump out the vapor in the condenser.

man from trane
06-23-2009, 08:41 AM
^ I love this forum! That's a great idea! I have 2 huge freezer evaps on a 4 1/8" line that I'll bet will hold quite a bit.