Pre-Testing a Vacuum Diffusion Pump

For Short Term Learning Discussions ONLY. This area is for CURSORY questions and connecting with other users ONLY. ALL technical contributions need to be made in the appropriate forums and NOT HERE. All posts are temporary and will be deleted within weeks or months. You should have already search the extensive FAQs in each of the forums before posting here as your question may already be answered.
Post Reply
Joshua Guertler
Posts: 47
Joined: Fri Apr 21, 2017 2:59 pm
Real name: Joshua Guertler

Pre-Testing a Vacuum Diffusion Pump

Post by Joshua Guertler » Wed Jul 11, 2018 4:54 pm

Greetings fusor community,

I have recently purchased a MetroVac 033C diffusion pump off of EBay for a pretty fair price along with a 14 day return policy. Since this was an EBay product and had been noted to have some cosmetic wear, I was wondering if there would be a way to test the diffusion pump to make certain that it is fully functional without hooking it up to a fusor or other vacuum system.

If it helps, the diffusion pump has a heater and is water-cooled. thank you.

Joshua Guertler

Jake Wells
Posts: 84
Joined: Wed Mar 19, 2014 1:29 am
Real name: Jake Wells

Re: Pre-Testing a Vacuum Diffusion Pump

Post by Jake Wells » Wed Jul 11, 2018 5:21 pm

Use a multimeter to check the resistance of the diffusion pump heating coil. Diffusion pumps have no moving parts so it is hard to test them without hooking them to a vacuum system. This is all in the FAQ!
“The day science begins to study non-physical phenomena, it will make more progress in one decade than in all the previous centuries of its existence.”
― Nikola Tesla

Roberto Ferrari
Posts: 327
Joined: Tue Mar 02, 2004 5:21 pm
Real name: Roberto Ferrari
Location: Argentina

Re: Pre-Testing a Vacuum Diffusion Pump

Post by Roberto Ferrari » Wed Jul 11, 2018 5:25 pm

After checking electric resistance as suggested Jack, look for right insertion of the heater;
Check the flanges surfaces for no dents;
Check for no leaks of the main vessel ( water filling it in case has no oil on it).
Check water refrigeration circuit for no leaks or clogs and you are done.
Good luck,

User avatar
Rich Feldman
Posts: 1053
Joined: Mon Dec 21, 2009 11:59 pm
Real name: Rich Feldman
Location: Santa Clara County, CA, USA

Re: Pre-Testing a Vacuum Diffusion Pump

Post by Rich Feldman » Wed Jul 11, 2018 10:17 pm

There's an easy additional test, reported here by Muhammad Faizdul.

After cleaning the empty chamber, he filled it halfway with water and brought it to a boil. OP mentions one hazard.
Roberto already mentioned water filling as a way to detect gross leaks, without using vacuum.
A heater test by ohmeter (only) might miss things like mouse or spider nests in the bottom of the unit.
Mike echo oscar whisky! I repeat! Mike echo oscar whisky, how do you copy? Over.

Post Reply