Heat Pump => Vacuum Pump

[Inquisitor]

I’m having to replace my house’s heat pump. Would the compressor unit make a (serviceable) vacuum pump for fiber/epoxy work?

[cyclops]

NO. Because AC compressors have the oil circulate with the Freon. You will empty the crankcase in a few minutes and blow oil everywhere.

[SamSam]

Originally Posted by Inquisitor

I’m having to replace my house’s heat pump. Would the compressor unit make a (serviceable) vacuum pump for fiber/epoxy work?

I have one made from an AC compressor and it works fine. Ocasionally oil has to be added but it doesn't all just squirt out in a few minutes. Yours is going to be thrown away anyway, so try it and see. Sam

[cyclops]

Is yours a sealed crankcase? Rather than the open crankcase used in most home AC compressors.

[marshmat]

If your pump has separate refrigerant and oil circuits it would probably be workable. If it's open crankcase (refrigerant is also lubricant) then all you'll do is shoot refrigerant into your garage and burn out a motor.
You won't get nearly the vacuum that you can with a real vacuum pump, but if your unit is of the right type it could be serviceable.

[SamSam]

Originally Posted by cyclops

Is yours a sealed crankcase? Rather than the open crankcase used in most home AC compressors.

The whole unit is sealed, that is it's one piece that you can't take apart, but I believe it's an open crankase. In the vacuum line just before the unit I have one of those glass oil holder things with a valve that is set to drip maybe one or two drops a minute into the line which then goes into the compressor. The pressure line of the compressor goes into a soup can to catch what oil does come out there. My compressor came out of an AC unit, the local Carrier Guy told me that one out of a refrigerator would work better as a vacuum pump, but I can't remember what the reason was. Sam

[FAST FRED]

An air cond only pulls enough vacum to bring the evap plates down to 35F to keep water condensing on the fins from freezing.

Any fridge goes to much lower vacum to service the freezer section.

Old refrigerator cans work very well at reasonably small pull down areas.

There not big enough to pull all the air out of a hull moulding in reasonable time.

But do GREAT if a shop vac is used for the "big" air removal and all they have to do is the pull in.

Although its not OK for Boeing or Air Bust , a shop vac does a fair job at small stuff all by it self.

It will not compact laminate , but to stick a 3/4 thick foam into epoxy grout to repair a failed composite deck.

FAST FRED

[yokebutt]

It's free, give it a whirl, you'll need a vacuum-gauge anyway.

Yoke.