charging in the cold

[wilks]

hello guys ,

whats the best way to charge a system in a ambiant of say 3 to 4 oC . its a cold room on r134a and the condensing unit with the liquid reciever is outside.I know about covering the condenser up by part but what do you guys do ? thaks for your help

al

[Brian_UK]

Bucket of hot water to stand the cylinder in.

[Grizzly]

Or a heater blanket.
Personally I use a Bosch 110V Hot Air Gun.
You would be amazed how quickly you can transfer the refrigerant, once it has been warmed at the cylinder.
Grizzly

[chillyblue]

hello guys ,

whats the best way to charge a system in a ambiant of say 3 to 4 oC . its a cold room on r134a and the condensing unit with the liquid reciever is outside.I know about covering the condenser up by part but what do you guys do ? thaks for your help

al

Did you mean the system charge??
I think it's very easy to over charge a system with low ambient as the liquid backs up in the condenser, but won't cause a problem til the warmer weather comes, when it will start tripping on HP.
I had a similiar problem yesterday, low ambient the sight glass just did not want to fill, i went by subcooling and cabient temperature in the end. still not certain though.
CB

[wilks]

Did you mean the system charge??
I think it's very easy to over charge a system with low ambient as the liquid backs up in the condenser, but won't cause a problem til the warmer weather comes, when it will start tripping on HP.
I had a similiar problem yesterday, low ambient the sight glass just did not want to fill, i went by subcooling and cabient temperature in the end. still not certain though.
CB

yeah thats what i mean cb, couldnt get no heat in the liquid line , had to cover nearly all the condenser

[Gary]

Without covering the condenser, charge until the coil outlet superheat is normal. This is the minimum charge needed to do the job under current conditions, but a little more may be needed for colder conditions, so...

Cover the condenser until the SCT is up near design pressure. Then add refrigerant until the receiver outlet subcooling is about 15F/8.5C. This is the maximum charge, but could conceivably be excessive for hot ambients if the receiver is undersized.

Anywhere in between will work.

[wilks]

thanks gary , makes sense now !

[wilks]

Without covering the condenser, charge until the coil outlet superheat is normal. This is the minimum charge needed to do the job under current conditions, but a little more may be needed for colder conditions, so...

Cover the condenser until the SCT is up near design pressure. Then add refrigerant until the receiver outlet subcooling is about 15F/8.5C. This is the maximum charge, but could conceivably be excessive for hot ambients if the receiver is undersized.

Anywhere in between will work.

dont really get hot ambients here in liverpool so that should work fine. hottest about 20 oC to 25 oC max summer

[icecube51]

take some old compressor heaters and fit them to you're bottle.2 ore 3 will do in cold weather. safe - clean and handy.

[malik55]

Is it not possible to charge your system by weight, measure the required amount and just fill it, Only it needs that you have a unit name plate with refrigerant charge mentioned on it and a charging scale.