Pulling refrigerant into condensing unit

[hvac meister]

The guys I work with have differing opinions on pulling the refrigerant back into the condensing unit for quick repairs. This is concerning only residential split units. Not heat pumps. 2 to 5 ton units. One question is about safety. If the system has a extra long line set can it be dangerous to pull all the refrigerant back into the condensing unit? Also, in general, my opinion is that it is best to recover the refrigerant. That way you know how much was in the system to start with plus it is better with these small units to simply use new clean refrigerant. Any feedback would be appreciated. Thanks.

[ryan1088]

If I don't suspect a charge problem, then I'll pump back what I can before the compressor internally bypasses then recover the rest.

If I suspect there's something up with the charge then I take it all out. Especially if the factory installed drier is still in the condenser.

Really for me is a case by case basis.

[jrmTexas]

Newer scroll will go into bypass if condenser is full, older units you have to watch the amps and listen to the unit. Once unit is full close service valves and recover remaining line set. 95% of time a properly charged unit with a reasonable line set will pump into condenser without a problem. I've pumped hundreds of units into condenser to replace indoor coils, replace leaking driers and repair minor leaks in lines. If I have a large leak on a coil or line set I never pump the unit into condenser, just to avoid possibility of pulling non condensables into the system. If the system was so low that the suction side was pulling into vacuum with system running you should recover the system just to be safe.

[Barrettservices]

If I don't suspect a charge problem, then I'll pump back what I can before the compressor internally bypasses then recover the rest.

If I suspect there's something up with the charge then I take it all out. Especially if the factory installed drier is still in the condenser.


Really for me is a case by case basis.

X2 i pump into the condenser until the low pressure switch cuts out then recover.

One thing i have always heard is that it can damage the scroll tips once you get below 20psi. Is this true because i have gone on calls where scrolls have pulled a vacuum due to restrictions but after i correct the issue and recharge these compressors have still kicked for years.

[ryan1088]

X2 i pump into the condenser until the low pressure switch cuts out then recover.

One thing i have always heard is that it can damage the scroll tips once you get below 20psi. Is this true because i have gone on calls where scrolls have pulled a vacuum due to restrictions but after i correct the issue and recharge these compressors have still kicked for years.

I've had pretty good luck with not doing damage under 20 psi for a short period of time. The couple that I know for a fact died from running in a vacuum, ran that way for an unknown amount of time.

[Barrettservices]

I've had pretty good luck with not doing damage under 20 psi for a short period of time. The couple that I know for a fact died from running in a vacuum, ran that way for an unknown amount of time.

Thanks. Thats kinda what i figured.

[Barrettservices]

I've had pretty good luck with not doing damage under 20 psi for a short period of time. The couple that I know for a fact died from running in a vacuum, ran that way for an unknown amount of time.

Thanks. Thats kinda what i figured.