Originally posted by MattyRay
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VBM Domobar brewing issue
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That's good to know thanks MattyRay. It appears that it's normal then, and I shouldnt stress too much over it..Last edited by tampinator; 9 May 2017, 03:17 PM.
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FWIW, I have a Domobar Jr set to 9 bar and it makes the same noise.
Regards,
Matt
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I noticed on a certain coffee spare parts site (not sure of the forum rules regarding posting web addresses) I can purchase a fluid-o-tech OPV for VBM domobars... Do you think the change over could be of benefit?Originally posted by MrJack View PostEdit: It has a small fluid-o-tech OPV.
I'm almost game to make the switch over if it'll make a difference and is possible... part costs $27.90 plus postage from NSW so it won't break the bank either..
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Thanks MrJack. Is your machine a VBM domobar and set to 10 bar??Originally posted by MrJack View PostAt lower discharge pressures the pump is capable of greater flow - flow which needs to be diverted via the OPV. The whining noise may be a result of higher velocity flow through the OPV. I get it occasionally in my machine and that is what I have attributed it to.
Reason I ask is because I'm trying to figure out if this noise is a VBM only issue or a HX machine with a vibe pump issue..
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I think it is fair to assume they don't. On a rotary the pump has its own internal bypass that controls the pressure at the pump outlet, typically at 9 bar. The OPV is merely a safety device set considerably higher and shouldn't open during normal use unless the pump pressure controller fails.Originally posted by tampinator View PostI have mine currently set to 11 bar and there isn't any noise.. I'd ideally like it at 10 bar and I'll happily put up with the noise if I know it won't lead to any issues.. based on your comments it appears that I should be fine so I appreciate your feedback! Would it be safe to assume VBM owners with rotary pumps dont have similar issues??
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At lower discharge pressures the pump is capable of greater flow - flow which needs to be diverted via the OPV. The whining noise may be a result of higher velocity flow through the OPV. I get it occasionally in my machine and that is what I have attributed it to.
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I have mine currently set to 11 bar and there isn't any noise.. I'd ideally like it at 10 bar and I'll happily put up with the noise if I know it won't lead to any issues.. based on your comments it appears that I should be fine so I appreciate your feedback! Would it be safe to assume VBM owners with rotary pumps dont have similar issues??
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I know this noise can be irritating. When I had my machine serviced, I asked the technician to adjust the OPV to 10 bar (where I had set it at previously after doing the descale). When I picked it up again, hè said hè could not get it to work below 11 bar, but I found the noise had returned nevertheless. After several months of use however the sound waned and I left it at that. Only recently I repeated the descale, provided a bit of thread sealant on the OPV outlet and readjusted it too 11 bar. Occasionally there is a bit of a squeak but it ceases If I run a few backflushes. Maybe the spring needs breaking-in. I have stopped worrying about it now, since unlike you I have not found a strong difference in taste between the stock setting of 12 bar and a lower setting.
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Thanks degaulle, I tried that with my old OPV with no success, and ended up purchasing a brand new OPV. The noise unfortunately is still there..Originally posted by degaulle View PostThis seems to be a fairly common phenomenon with vibe pump machines that have their brew pressure maxed out by an OPV. On my machine I have been able to at least reduce the squeak by unscrewing the internal part and soaking it in a descaling solution for half an hour or so. It may be that there is a tiny bit of scale deposit that somehow makes the OPV sensitive to this when you loosen the spring to reduce the pressure.
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This seems to be a fairly common phenomenon with vibe pump machines that have their brew pressure maxed out by an OPV. On my machine I have been able to at least reduce the squeak by unscrewing the internal part and soaking it in a descaling solution for half an hour or so. It may be that there is a tiny bit of scale deposit that somehow makes the OPV sensitive to this when you loosen the spring to reduce the pressure.
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VBM Domobar brewing issue
Hi guys, long time reader first time poster...
I have VBM domobar which as been running like a dream since new. From new the brew pressure max's out at 12 bar.
After reading some threads on this site about adjusting the OPV to reduce the brew pressure to 9 bar (10 bar on the gauge) I decided to give it a go and managed to do it with no real hassle. My coffee shots taste soo much better also!
The only issue I have is I get this high pitched ringing noise from the water pump when I max out at 10 bar.
I readjusted the OPV and realised the high pitched sound picks up when I set the OPV anywhere from 8 - 10 bar max. If it sits lower or higher on the gauge the sound goes away.
I even tired replacing the water pump and OPV with no success...
Will this affect the machine in the long run? If so, what could be the issue??
Cheers in advance!!Tags: None
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