# Domobar internal leaks



## lukefinegan (May 16, 2013)

I recently picked up a Vibiemme Domobar secondhand, after a bit of fiddling this afternoon I managed to pull some great shots. However I've found a couple of leaks and need some advice sorting them out.

The thermowell appears to spit water at the top of the brewing cycle, here:









The OPV is leaking from the screw:









Any easy fixes? Should I just replace the parts? Also I have noticed what look like 'iron filings' in the brew water...what might they be?

Thanks


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## urbanbumpkin (Jan 30, 2013)

Iron filings.....Have you descaled recently?

I'm sure I've read that descaling solutions can take the chrome coating off some parts and lead to this. Can anyone confirm or have I dreamt this?


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## espressotechno (Apr 11, 2011)

White teflon sealing tape is your friend.


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## lukefinegan (May 16, 2013)

Yeah I was thinking I could just put Teflon tape around the screw, but what about the thermowell? The water appears to be coming out of the centre, not around the seal. And yes I have descaled recently, so hopefully a couple more flushes will clear it out.

Cheers for any advice.


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## lukefinegan (May 16, 2013)

So PTFE tape fixed the opv valve. Cheers espressotechno. I unscrewed the thermowell and it seems in good order I've put fresh tape around the seal there and it seems better. I love an easy fix. Now to make some coffee!


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## DavecUK (Aug 6, 2013)

lukefinegan said:


> So PTFE tape fixed the opv valve. Cheers espressotechno. I unscrewed the thermowell and it seems in good order I've put fresh tape around the seal there and it seems better. I love an easy fix. Now to make some coffee!


Teflon tape is not correct for the OPV screw. The Expansion Valve (OPV) doesn't leak at that screw by virtue of an O ring. The thread is not the place it should be sealing at. Also on yours the screw looks to be adjusted well out, perhaps a little too far...if you are needing to do this to get 9 bar, then it indicates some other potential problem. you should remove the screw and inspect the O ring, you can also see how near the sealing ring is from the top of the barrel. The part is inexpensive to replace and may well be worth doing.

Often on these cheaper expansion valves, it's very difficult to adjust them down to 9 bar and leaking is a common problem when you try to do so. it's why loads of machines with these expansion valves are adjusted to around 10.5 bar. Some variants of them will just allow you to adjust down to 9 - 9.5 bar.


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## 7493 (May 29, 2014)

One of the documents I linked to suggests that it may be necessary to reduce the expansion valve spring by one coil in order to obtain a satisfactory 9bar adjustment. I was lucky and didn't need to do this and my screw is not sticking up the way yours is. (Mine was running at around 11bar before adjustment.)


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## lukefinegan (May 16, 2013)

Yeah I did read that article. Thanks for the post. It's running at around 9 bar now and the tape seems to have stopped the leak. I'm really pleased with the machine it makes great coffee. Much more forgiving than my Silvia. I fitted a single hole steam tip and getting some great milk now aswell!


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