Question about flushing AC..please read - PeachParts Mercedes-Benz Forum

KylePavao · #1 06-19-2006, 09:41 PM

I ordered this Venturi AC pump from Harbor Freight...to dry the system and suck all the moisture out.

All the AC shops around here charge ridiculous amounts, and the dealer wanted to charge 600 just to convert to R134A!!

Well I didn't want to get raped by the dealers, and I am confident that my compressor is in good shape as it blows somewhat cold air now, and its the old piston type York compressor. Its HUGE!

I have a 10HP air compressor.

My question is, where does all this moisture accumulate after I get a vacuum on the system? Does this go inside the box? Someone have any ideas? I was thinking of simply not drying it, but for this price, I figured I might as well do it the right way (sort of) AC shops don't want to just flush the system for me, they insist on doing the rest of the job (400 dollars +!)

tangofox007 · #2 06-19-2006, 10:18 PM

The air from your compressor will flow through a venturi tube in the box. Air flow created by the low pressure portion of the venturi essentially mixes with the air from the compressor and blows out, taking water vapor with it.

I hope that you understand that flushing and evacuation are two different steps.

leathermang · #3 06-19-2006, 11:07 PM

Kyle, You made a mistake buying that machine for the purpose of vacuuming AC systems... we have said that in many threads... but here is one from Aircondition.com to that effect also...

http://www.aircondition.com/tech/questions/38/Air-Powered-A%7B47%7DC-Vacuum-Pumps

If you did not want to buy a good vacuum ( I can understand that ) then you could have rented it from a local equipment rental for a weekend...

The old style vacuum pumps just had a hole which the water would drip out of..

KylePavao · #4 06-19-2006, 11:09 PM

I understand somewhat, but could someone fill me in on the details?

I assume evacuation is the removal of the refrigerant and oil that comes with it, and the flushing is the use of some sort of AC flush product (like on Dieselgiant) to flush contaminants from the system.

Matt L · #5 06-19-2006, 11:12 PM

Removing the refridgerant is reclamation, not evacuation.

Flushing has nothing to do with a vacuum pump.

Evacuation is the process of removing gasses, in order to remove all noncompressables and water.

KylePavao · #6 06-19-2006, 11:13 PM

This thing is worthless then, eh? Even with a huge industrial type aircompressor (over 10HP, which I have access to) this won't do me much good?

Matt L · #7 06-19-2006, 11:14 PM

Not worthless, but it won't pull as good of a vacuum as a vane pump. It would do in a pinch, but you're better off with a deeper vacuum (less gas in the system) for best long-term performance.

leathermang · #8 06-19-2006, 11:16 PM

Kyle,

Here is what you need written by the PROS...

http://aircondition.com/tech/

KylePavao · #9 06-19-2006, 11:26 PM

Yes this looks like a good place..I'll need to check it out. I am replacing with Freeze 12, and it looks like I need the accumulator drier as well as the brass valve...

It sucks because I dumped one old can of straight R12 in there a year ago and it still blows somewhat cool, but I am not sure if I can throw this freeze 12 stuff in there.

Also the accumulator drier for the 123 is only 25 bucks..while the W115 one is 60 dollars! Ahh

leathermang · #10 06-19-2006, 11:52 PM

Some of your statements make me think this site would be helpful also...

http://www.epatest.com/manual609.html

There are no 'drop-in' substitute refrigerants for any equipment category. This means that some changes in a system's equipment or materials of construction are always necessary when converting to a replacement refrigerant. The existing refrigerant cannot simply be removed from a system and replaced with another refrigerant. Usually the changes amount to replacement of incompatible seals and changes in lubricant. Filter-driers, compressors, and seals that are compatible with CFCs, HCFCs, HFCs and their oils are currently being developed; however, the replacements are not without problems. The new (POE), synthetic oils being used with HFC refrigerants are incompatible with as little as 1% residual oil, (PAG or traditional mineral), in the system.

NOTE:
HFC-134a still carries some concern about compatible lubricants. Lubricants typically used with CFC-12 do not mix with HFC-134a. Polyalkylene glycols (PAGs) mix properly with 134a at low temperatures but have upper-temperature problems, as well as incompatibility with aluminum bearings and polyester hermetic motor insulation. Ester-based synthetic, (POE), lubricants for HFC-134a resolve these problems but are incompatible with existing PAG or mineral oils.