Vibiemme Domobar Super HX Water Pump

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DirtyLittleSecret
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#1: Post by DirtyLittleSecret »

Thanks in advance for anyone who can help diagnose this issue.
Our trusty Vibiemme Domobar Super HX (of over 10 years) recently had a failed water pump (literally melted).
Replaced the water pump with an ULKA EAX5 and noticed it wouldnt turn off. Figured the solenoid switch or water level gauge/Gicar water fill level box probably went bad and replaced those as well as they've already lived a long life. Thought it also might be an obstruction so replaced all silicone lines, one-way valve and cleaned the pipes as I figured its not going to hurt and that it was about time for a tear down...Still, the water pump wont turn off.
Have confirmed water is getting to the group head, and the water gauge is showing 8 bar while the pump is running. What else am I missing that controls the water pump?
Any other thoughts would be much appreciated!

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bengee
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#2: Post by bengee »

A melted pump? Never heard of that, sounds like a serious electrical brain box.

That "missing" grey box (that controls the water pump and many other things) that you are looking for is actually a black box, the control box, the brains of your machine. Maybe something is going wrong there. They are a few hundred dollars to replace and a few outfits do fix them. Perhaps someone here will have a protocol to propose to test if it is the source of you problem.

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Randy G.
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#3: Post by Randy G. »

If we assume that the wiring has not been damaged, and the rewire job was done correctly, then remove the auto fill ware from the boiler and use a jumper wire to ground it to the chassis. Turn the machine one. The pump should not start. If that is true then the boiler is scaled as is the water level sensor.
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erics
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#4: Post by erics »

While you are doing this troubleshooting, disconnect one of the leads to the heating element. You DO NOT need heat to solve this problem.

The boiler is calling for water when you turn the machine on (that is pretty normal) and, if no water is getting to the boiler (via the fill valve), then my guess would be that the boiler fill solenoid is either very clogged or the solenoid coil itself is inoperative.

Another (very rare) possibility is that the brew lever switch has failed closed.
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

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Randy G.
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#5: Post by Randy G. »

erics wrote:Another (very rare) possibility is that the brew lever switch has failed closed.
I would not have thought of that! Good call! Also check the adjustment (position) of the switch's position for clearance between the exterior cam and the plunger (I wouldn't have thought of that if you hadn't mentioned failure of the switch).
EspressoMyEspresso.com - 2000-2023 - a good run, its time is done

DirtyLittleSecret (original poster)
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#6: Post by DirtyLittleSecret (original poster) »

Thanks for all your input! Here's what I've done:

Seeing as there is no computer (this is the manual Domobar Super HX) there isnt a "control" box - easy one to diagnose!
Im pretty religious about descaling and ran a pipe cleaner through several of the mains. Very little scale.
Jumpered the boiler fill sensor and had water coming out the boiler safety valve (seems we have plenty of water and the head pressure is good).
Tested the lever micro switch and bingo! Looks like we have a winner! :wink:

Ordering a new lever micro switch today and will let you know if this solves the issue.

BTW: how many cycles is the main power switch good for? Noticed the clear rubber seal is discoloured from years of heat cycles and just wondering if it would be good measure to install a new one while Im at it? Ive gone through several pressurestats over the years and keep "on" 24/7.

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erics
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#7: Post by erics »

. . . and just wondering if it would be good measure to install a new one while I'm at it?
Rather than replace, I would suggest you practice your dexterity (and patience) and tighten all the wire connecting screws.

Also, take a very good look at the incoming power connector.

You can also temporarily install a simple toggle switch in series with the brew switch until the replacement arrives. Syphon a cup or so of water out of the boiler and let the autofill do its job with the brew switch disconnected. I would discontinue 24/7 ops until the new switch is in place. You also should install a "Klixon" thermal cutout for the vibe pump - https://www.espressocare.com/products/i ... al-cut-off .

Almost all machines discussed on this forum have a control box . . . it is a question of semantics.

Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

DirtyLittleSecret (original poster)
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#8: Post by DirtyLittleSecret (original poster) »

Eric-
Thanks again for the input and the schematic. Placed my order with Stephanos Espresso Care and nabbed a thermal switch as well. I think I noted in the OP that the Gicar controller was replaced. If not, my lack of oversight! I replaced the pigtail but will take a look at the main switch connections. Am seriously thinking about just doing a complete rewire to make sure any old/cycled wire gets replaced with sound wire for another 10 years of service.

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erics
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#9: Post by erics »

Am seriously thinking about just doing a complete rewire to make sure any old/cycled wire gets replaced with sound wire for another 10 years of service.
Vibiemme (and likely others) subcontracts their wiring harnesses. I found a problem with the main power connection and hence my suggestion to simply look at it. I judge this to be a "one-off" problem and certainly not a machine trait.

The Vibiemme wiring is pretty darn good as is so I would have 2nd thoughts as regards the rewiring.

It is a robust machine and since you are in Oregon and Stefano is in Oregon . . . you have it made.
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

DirtyLittleSecret (original poster)
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#10: Post by DirtyLittleSecret (original poster) »

Final update:
Replaced the switch and added the water pump thermal switch...all is well again.

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