Post by turbokinetic on Sept 23, 2018 13:05:13 GMT
Also, the vacuum that your friend got - what are the details on it? I'm wondering now if I need to evacuate my DR1 that has a restriction, so I can get that squared away.
Hey Paul - I got a cautionary tale. If you evacuate SO2 residue with a vacuum pump, be mindful of the chemical properties of the SO2. It is very corrosive if and only if it combines with water. Most of us use vacuum pumps to remove moisture from systems, and therefore the vacuum pump oil collects water. I very nearly destroyed my "good" vacuum pump the first time I evacuated a system which had SO2 residue with it. It was actually locked up the next day and I had to dismantle it to free it up. I'm sure there has been a loss of efficiency because of this incident.
On the next project, I changed the pump oil before and again after the SO2 residue removal. No problems.
The way I do it now, is to use a pneumatic vacuum pump (ejector / educator / venturi style). This has no moving parts and is powered by compressed air. I built an extended vacuum hose which fits the air-vac pump, and allows the pump and therefore the exhaust to be outside. I then evacuate with this. These don't pull down like a mechanical pump will; so I follow up with an hour run of the good old mechanical pump to ensure it's done!
Here is one example of the air powered vacuum pump: shop.advanceautoparts.com/p/mountain-air-vacuum-pump-mtn8405/22989189-p
You need an air compressor with a lot of capacity to run these pumps, otherwise the compressor will run constantly and may overheat.