Pump not taking in water, but it is running... [SOLVED]

Equipment doesn't work? Troubleshooting? If you're handy, members can help.

Postby CeeeWeee » Nov 12, 2017, 1:59 pm

Hi Forum,

Hope you can help med out. I inherited an older Vibiemme Domobar. But there seems to be a problem with the water intake.

Powering on the machine works fine - it heats up like it is supposed to. But upon pulling the lever (to up position) there is not water coming into the group head. I did disassemble the top and botton nutches on the group head to see if there were any blockages - nothing to see. And when i had the group head open and pulled the lever, still no water came out.

I took of the cover to see if there seemed to be any leaks - there is not. I then noticed that even though the pump seems to run fine (making the "normal" noise) - it actually does not take in any water at all. Also when trying the water switch (below steam) the pump is active but with no water.

I would like some tips for me how to check if the pump needs replacement. That procedure is probably not that hard - but I would be happy if one of you could confirm that it sounds like the right thing to do. Or are there other tips for me to try?

Many thanks!

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Postby bengee » Nov 13, 2017, 1:25 pm

Hi! My guess is that your pump is toast.

You can remove it from the machine quite easily with a wrench. To test my pumps, once removed from the machine, I plug them straight into the wall with a power cord and observe and measure the output. If it's working fine and has a normal debit rate, you might have a blockage somewhere else in the machine. If it's now pumping or if in doubt, swap the pump for a new one!


Postby Nunas » Nov 13, 2017, 3:25 pm

Test 1: Is there water going back into the tank on the back flow hose? If so, your pump is working and the check valve is probably stuck closed. This can happen if a machine is stored for quite a while. If no water, then as mentioned your pump is probably u/s.
Test 2: Remove the mushroom from the group head and start up the machine in an area where you don't mind getting water all over the place. If water comes out then the problem is downstream.
Test 3: If water in test 2 look for a plugged screen or plugged gicleur. On the bottom of the mushroom there are four holes that feed the gicleur chamber. Look for a blockage.


Postby Nunas » Nov 13, 2017, 3:34 pm

PS I think the Vibiemme Domobar comes in a vibe pump version and a rotary. The vibe pump if worn can still make its characteristic sound, yet not move any water if the internal diode is blown. The rotary pump is actually a pump connected to a motor. The motor can be good and making noise but the pump may be bad. This may be obvious :) ...

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Postby slipchuck » Nov 13, 2017, 8:03 pm

If it was sitting a long time it might possibly have an air lock. I just bought a used Breville infuser that sat for a long time... it took a good 20 minutes to get any water moving at all.

Good luck!

“There is nobody you can’t learn to like once you’ve heard their story.”


Postby CeeeWeee » Nov 14, 2017, 2:03 pm

Hi all,

Thank you for the replies. The machine has actually been out of use for about 3 years. So there could be some air lock...not sure.

A new pump should arrive tomorrow - i hope that does the trick. In any case i think it could be good with a new pump...then i will work from there.

I will keep you posted how it works out. :D


Postby bongani » Nov 14, 2017, 4:10 pm

On a sidenote, with a new pump on route, I think this is your chance to study the broken pump and attachments. This will prep you for future mishaps. For all we know, you may be cake to figure out what's wrong and end up with a spare for future use or be able to help should the need arise.

Good luck with everything. Here's to hoping and wishing that you enjoy your new machine.


Postby CeeeWeee » Nov 15, 2017, 1:54 pm

Hi all!

Sucess!!! :D

The vibration pump is changed. I used PTFE tape and the operation was fairly simple. Pump is working!

I filled the boiler - emptied it - filled it with descaler - waited 45 minutes - emptied the boiler - ran through 1,5-2 liters of fresh water through the group and steam arm.

All is well. Pulled the first 4 espressi - just great stuff.

(i have not checked what happened with the old pump - but as was mentioned I would have a look at it and have it as a spare for future)


Postby Nunas » Nov 15, 2017, 8:39 pm

Vibe pumps are not worth fixing. If you do take it apart, be sure not to lose the tiny ball bearing.

Important note re vibe pumps (ULKA anyway). They are 50/50 duty cycle with no more than 60-seconds run at a time. Violate this and eventually the internal diode will likely burn out.