Hey there, having some issues with a Welch 2052-B diaphragm pump. Ordered a diaphragm replacement kit and swapped them all out yesterday. 3 out of 4 had failed and new install was a breeze. However the pump is still making a loud ‘squeaking’ noise and does not seem to be pulling vacuum. The air outlet port seems to be blowing normal but the vacuum inlet seems to be mildly blowing air versus pulling air. First time pulling one of these apart, anyone experience this before? What am i missing? Thanks in advance!
Did you replace the little check balls too? Depending on what material they are made of, they may shrink or expand with time, might need to swap those as well?
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this one doesn’t have the balls although i’ve done this on other pumps… just a flat one piece diaphragm that mounted into the inner shaft via threaded screw in center.
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for ref.
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take it apart and try again. sounds like
you’ve got a check valve that is installed incorrectly or missing
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Yes this part is always tricky. One side has a sheen to it, and the other is dull and it needs to face a specific direction. Even after replacing parts in these pumps several times, my eyes struggle to see the difference sometimes.
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Which way faces which lol
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- Insert the valves (3) and the O-rings (4).
Ensure that they are lying completely flat. Do not insert the burred side facing the sealing surface. Align the connection
head flush with the pin.
strangely enough I’ve not actually pulled one of these particular critters apart…I generally pay @Xtractek to do these for me.
simply working from first principles…if it’s blowing out the vac port, there is a check valve not doing its job.
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given the construction, you should be able to figure out which valves are the problem ones from the outside (each head has it’s own in & out port).
in which case the correct direction is “the OTHER one!” 
based on the fact that your sucker is blowing, I would guess it’s the valve closest to the vac port. if it was any of the others, you’d get less suck, not blow, based on my understanding of how it works (haven’t read the manual, or pulled one apart…they might be in parallel rather than series).
only one way to find out…
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pro tip: from an efficency standpoint, this was dumb.
you started having performance problems when the first diaphragm failed, somebody should have raised their hand. It got worse. still nobody mentioned that shit just wasn’t working like it used to. that it took longer to get to vac, and it didn’t seem as deep. after having performance issues for what may have been months, the third diaphragm fails. how long did it take for somebody to raise their hand?
maintenance of mission critical equipment should be proactive not reactive. if you’re still figuring out what your maintenance schedule looks like, at least pay attention when your equipment says it could use some help.
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This is typical with these pills. That’s why vacuubrand reigns supreme in this type of pump. I’ve had numerous welch complaints early in my business so we stopped selling them bc of the constant complaints from customers.
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Could you be more specific?
Do you mean “it is typical for first time rebuilders to get atleast 1 of the four directional check values in backwards”?
if they only get the “sucker blower” phene when the get the final valve in wrong, I can see a lot of folks fixing the suck out of these things and never figuring that out.
I’m not disagreeing with the “vacubrand does this better”. My pump guy has told me the same thing. I’ve passed it along.
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depends. I do know tho welch isn’t what welch was a decade ago… There’s Teflon parts that are coated on the inside that peel sometimes when being rebuilt once. So that’s also something that I don’t like hearing customers or rebuild centers tell me they encounter.
this actually happened from a tech overfilling a collection tank and pumping liquid through it in a matter of a minute. i do know how to diagnose a problem at first sight
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But do your techs ALL know when to raise their hands?
My experience is that part is an acquired skill
might be an obvious suggestion but if i remember right there might also be a check valve on the white tubing running from head to head that would be easy to place in the wrong direction as well. other than that yeah it’s v likely the flappy bois mentioned earlier and i would agree those are the trickiest part of these rebuilds, sometimes its as simple as them falling slightly out of place when you place the head on to fasten it in. you may just have to trial and error your way into turning each one in each head one at a time, etc. etc. i’ve had to slog through a few of these, its an exercise in patience and persistence, i wish you the best of luck
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Hmmm…I wouldn’t expect liquid to take out three diaphragms.
Although that’s without wrapping my head around the interplay between heads.
I’ve had the same thing happen, and the pump seemed to run better after it was rinsed out with fresh ethanol.
Pretty sure I then played that trick with a couple more that had been pulling decarb duty & improved their function too.
Could be hallucinating.
They might ALL have blown three diaphragms.
Didn’t put a gauge on a one of them.
Might not have run them as long either?
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hallucinating for sure, lol
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My pump guy confirms that flushing “oil” (crude) out with ethanol works just fine on those critters.
I recall having done so DELIBERATELY atleast twice. I’m going with NOT hallucinating.
…this time
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Got er running good today lol only took me 4 times