Yellow Jacket Super Evac Problems

[advancedhac]

Just purchased a used (looked really clean/almost new) yellow jacket 6cfm superevac pump. Although it isn't pulling a full vaccuum, it's stopping right around 1000" range where these units "should" pull to around 30". Has anyone seen this before? Cost alot to fix these?

[kiwireeferman]

Have you tried changing the oil?

[advancedhac]

Yep, I've replaced it multiple times - even with Yellow Jacket brand oil. Nothing changes...

[hvacsteve82]

Now we know why the person sold it....

[advancedhac]

Ya, I'm trying not to think about that...

I just talked to a Yellow jacket service center, and they said that it might just be a problem with the vacuum gauge on the unit. They said "great pump, but the integrated gauges don't last long" So... hopfully that is all that wrong with the darn thing.

I need to get my hands on a decent thermistor micron guage.

[amickracing]

#1 problem... if you have a fitting on there so you can attach either a 1/4" or 3/8" hose, the cap on which ever part your not using could be leaking (or the fitting that goes into the pump itselt). Pretty common thing to over look. Could also be that gauge them mentioned. Is there anyway to take it off and plug it?

#2 problem... bad hoses or connections?

#3 ... inacurate measurement (weak batteries or dirty micron gauge).

#4... really dirty pump. My POS pump would pump down to 300 microns, but it would take forever to get there. Yanked the front cover off, cleaned everything real good (there was a ton of rust and slime in there). Oiled it back up, let it run for 20 minutes capped off. Changed oil and now it pulls down much faster (still not as good as new, but much closer).