Hi Guys..
Just wondering.
I'm evacuating a large air cooled condenser which had a lot of moisture in it.
I have 1 connection, teeing off to 2 vacuum pumps. Alternating one to the other as their oil turns milky thereby maintaining 1 vacuum pump operating at all times. The vac pump oil colour has now stabalized.

Now.. As I am running out of time, I'm thinking of running both pumps together to speed things up, but I'm a bit concerned that, since I only have one connection at the condenser, and if one pump has better efficiency than the other, could they begin to counter act each other and therefore slow the evacuation process all together,??...

Your thoughts would be greatly appreciated.

Peter