New life for a salvaged fridge compressor...we know she blows...

[Knotgoalie]

...but will she ****? Yesterday I bid farewell to 20yr old bar fridge that has seen better days but not before dragging it outside by the scruff, cutting it's main arteries and extracting the compressor out of it's warm...dead....corpse! The compressor itself checks out okay on the old Fluke mightymeter but it needs a new starter (thermal switch is fine) and should be good to go.

I know it is a dandy little high pressure compressor (LG NSA30LACG) but I'd like to see how it does as a vac. pump. Not a tough project and I'm curious if anyone else has done this before?

 

[rsanter]

They make a great vac pump.
A friend and I put one in a wood box, added a few fittings and made it into a vac pump for evacuating AC systems. We even set it up so it could pump the old from into the old used Freon containers so we were not dumping it into the atmosphere.

People that do woodworking, specifically laminating will use them as the vac pump for use with the vacuume bags

 

[Knotgoalie]

rsanter, very good to know as I have read so many opinions on both sides of the fence on the topic. I'm thinking of many uses, one being a chamber vac unit for sealing food in bags. I only have to add an electric sealing bar to a vac chamber to hillbilly a unit that can cost thousands. I already have two FoodSaver machines, one which I use to seal bags and the other is dedicated to large~med~small canisters for sealing mason jars. I have a wide mouth mason jar attachment that works directly on the jar but for regular mouth jars I use the canisters.

A chamber vac of sufficient size could hold a couple of dozen jars on a couple levels and all get sealed at the same time, one pull! The chamber also allows me to use any type of "smooth both sides" bag instead of being tied to the "ribbed for your pre$$ure" bags that the external vac machines require. There are work arounds but it is a pain to deal with.

 

[MattT]

They make a great vac pump.
A friend and I put one in a wood box, added a few fittings and made it into a vac pump for evacuating AC systems. We even set it up so it could pump the old from into the old used Freon containers so we were not dumping it into the atmosphere.

Did you ever put a micron gauge on it? I'm curious how deep a vacuum a compressor will pull.

 

[rsanter]

Did you ever put a micron gauge on it? I'm curious how deep a vacuum a compressor will pull.

We used the gauges for charging AC systems.
I don’t recall the exact numbers but it did everything needed to evacuate an AC system and verify holding vacuume before charging.
As long as the pump is fairly good they will pull a great vacuume

 

[Knotgoalie]

The "donor heart"...

 

[Knotgoalie]

They make a great vac pump.
A friend and I put one in a wood box, added a few fittings and made it into a vac pump for evacuating AC systems. We even set it up so it could pump the old from into the old used Freon containers so we were not dumping it into the atmosphere.

What did you use to oil the pump?

 

[Richard Cranium]

this is my question also.

 

[Knotgoalie]

this is my question also.

Hey, I may be new here but I'm not just pretty to look at!

 

[bonneyman]

Since refrigerators run such a low temperature (and correspondingly, pressures), they are good for make-shift vaccum pump use. The comps are made to run for extended times with little back pressure.

As far as oiling it, hmmm, never really thought about it. They do have oil circulating with the freon, so they need some lube. But I don't know how much reefer oil is in a normal refrigerator. Can't be much. I'd say get some reefer oil for it that has a temperature range of the work you're doing. Your local HVAC supply house should have that info. Add however many ounces is stamped on the housing of the comp, run a job with it, and pour the oil out. (Solder in a valve so you can turn the thing upside down and drain the oil). See if it's dark/burned smell. Go from there.

I know a low temp guy who was showing off such a comp he used for that exact purpose. Next time I see him I'll ask.

 

[Capt Chrysler]

Heck that is a new pump! Mine is from something out of the 50's. As it was the back up AC vac. pump in the dealership in 1983.

Capt. Chrysler

 

[Sjfab]

If it’s being used to evacuate a system in place of a real vacuum pump. That compressor won’t pull down deep enough. The deepest a recip will pull is around 22”. You need to get down into the microns in order to get all the moisture out of a system.

If it’s being used for wood working or another system where a deep vacuum isn’t needed, you’ll be fine.

 

[rsanter]

What did you use to oil the pump?

Nothing, but it does not get that much use so we don’t worry.
When it does, grab another one

 

[Showkey]

If it’s being used to evacuate a system in place of a real vacuum pump. That compressor won’t pull down deep enough. The deepest a recip will pull is around 22”. You need to get down into the microns in order to get all the moisture out of a system.

If it’s being used for wood working or another system where a deep vacuum isn’t needed, you’ll be fine.

^^^^^^thus is the correct answer

If you don’t understand deep vacuum for AC work or micron levels read this:

http://alltemp.ca/wp-content/uploads/2013/10/JB-Principles-of-Vacuum-Presention.pdf

 

[6PTsocket]

rsanter, very good to know as I have read so many opinions on both sides of the fence on the topic. I'm thinking of many uses, one being a chamber vac unit for sealing food in bags. I only have to add an electric sealing bar to a vac chamber to hillbilly a unit that can cost thousands. I already have two FoodSaver machines, one which I use to seal bags and the other is dedicated to large~med~small canisters for sealing mason jars. I have a wide mouth mason jar attachment that works directly on the jar but for regular mouth jars I use the canisters.

A chamber vac of sufficient size could hold a couple of dozen jars on a couple levels and all get sealed at the same time, one pull! The chamber also allows me to use any type of "smooth both sides" bag instead of being tied to the "ribbed for your pre$$ure" bags that the external vac machines require. There are work arounds but it is a pain to deal with.

I always resented the cost of Food Saver bags and always liked the idea of a commercial vacuum chamber but I never thought of making one. All the points you bring up about the bag design and COST are very true. What would you use for a chamber, that would not collapse under vacuum? I never gave much thought to the mechanics. Do you need a solenoid to press the heat seal bar down when the desired vacuum level is reached? I have never actually seen a vac. chamber sealer.

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