We got a DS42 in addition to the oil-less diaphragm pump with a new 5977 a year back. Our service guy looked the other way long enough for me to make the box diasappear. I installed it on a 5975 a year and a half ago and first thought I had a dead pump. Then I touched it and still thought I had a dead pump. I had to open the vent to hear the pump gurgle. It is the quietest pump I've ever had. It turns out, the DS42 is cheaper than the pfeiffer pumps. Thats the good news.
In the past two weeks I've heard different stories, one from an LCMS service tech and the other from a retired agilent consultant. The service tech says they are happy with the varian rough pumps and look to be switching over to them. The still active, but retired agilent consultant referred to a high failure rate (seals) as being a reason for getting away from the DS42.
I've been gathering up EM2s and DS42s and replacing the noisy pumps whenever possible. I had a dream about talking to 70 year old me, all he ever said was "Speak up sonny, I can't hear you. Did you say you're from the past? Would you swap out those noisy rough pumps and while you're at it, get off my grass." If I don't do something about it, 70 year old me is going to be a cranky, deaf dude. With this quiet lab, I can now hear the gentle chirping of the EPC shutting down while I do inlent maintenance.
