pump not starting sometimes

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ebprod

pump not starting sometimes

Post by ebprod »

For the last couple of weeks, my VII pump will sometime not start. It starts on the pre-infusion, then nothing. The next time I try it, it works fine.

It has been doing this about every other day, ever since I used citric acid to descale the machine. Did I do something to damage it? Is there some maintenance I can do on it?

I took the pump apart a couple of years ago and it looked clean at the time. I've owned the machine about 4 1/2 years.

thanks

-Joe
Endo

Re: pump not starting sometimes

Post by Endo »

Time to take the pump apart again and have a look.

Check for the classic shaft rust issue and at the bearings. Do a test of the motor alone to make sure it is actually the pump.

The descale solution is pretty aggressive stuff. It took the plating off some of my parts. :shock: It likely degreased something on your pump enough to cause it to stick.
ebprod

Re: pump not starting sometimes

Post by ebprod »

I took the pump apart, and this is what I found. There is a small spot of rust on the shaft. There is a powdery black substance, I don't know what it is- it is a bit greasy.

What is the next step?

-Joe
Attachments
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P1030499a.jpg (357.74 KiB) Viewed 6746 times
Endo

Re: pump not starting sometimes

Post by Endo »

Looks pretty good.

How does the pump feel when turned by hand? Any binding?

How about the motor? Does it start and stop OK?
ebprod

Re: pump not starting sometimes

Post by ebprod »

The motor runs freely.

I can turn the pump by hand smoothly. I don't know how much resistance there should be. I left the water hooked up, and I would say there was light-medium resistance.

can the pump be lubricated?

-Joe
Endo wrote:Looks pretty good.

How does the pump feel when turned by hand? Any binding?

How about the motor? Does it start and stop OK?
Endo

Re: pump not starting sometimes

Post by Endo »

ebprod wrote:The motor runs freely.

I can turn the pump by hand smoothly. I don't know how much resistance there should be. I left the water hooked up, and I would say there was light-medium resistance.

can the pump be lubricated?
I wouldn't try taking the pump apart. As I understand it, there are lots of little spring-loaded bits that would make re-assembly almost impossible as you see in this diagram:
Procon Pump
Procon Pump
procon.JPG (69.92 KiB) Viewed 6723 times
Also, if I'm not mistaken, there is no internal lubrication on these pumps (except for the bearings). I think the vanes are made of graphite.

Since it seems to turn freely, I can't say much more. Perhaps someone else might have some ideas (I'm a Mini owner so I only have experience with vibe pumps). Perhaps you can get some clues by reading some more about vane pumps here:

http://en.wikipedia.org/wiki/Rotary_vane_pump
ebprod

Re: pump not starting sometimes

Post by ebprod »

I cleaned out the black powder and up it back together. So far it seems to be working fine. I guess I'll just have to wait and see if it happens again

-Joe
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