# Noisy Brew (squealing)



## rogher (Nov 22, 2020)

I've been using a Rocket Cellini for a year or so, with filtered water and only occasional use.

No sign of scale but as I used to descale my previous machines fairly regularly (one used to tell me when) I decided to do so.

It started to squeal (if I knew how to add a sound track/video from my computer, I would) when pulling shots and has now got even worse.

The squeals are like I get when I back-flush (if that helps). Water is ejected into the drip tray and shots take longer to complete.

I think this is the OPV coming into operation (but now I may sound as if I know stuff, which I don't).

I'm looking for some guidance with where to go next...

Any suggestions (fire the Rocket is an acceptable one)?


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## DavecUK (Aug 6, 2013)

If you have a smartphone (most people do) with the YouTube app. Touch the icon indicated by the arrow









or the latest version looks like this









The make a video and it will upload an unlisted on YouTube, after which you paste the link here....all done. It's super easy.


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## NewboyUK (Jul 14, 2018)

Known squeal to be one way valves or OPV. If boiler water getting back to the pump that can make it squeal too. Also water starvation


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## MediumRoastSteam (Jul 7, 2015)

rogher said:


> I've been using a Rocket Cellini for a year or so, with filtered water and only occasional use.
> 
> No sign of scale but as I used to descale my previous machines fairly regularly (one used to tell me when) I decided to do so.
> 
> ...


 A video would be great. If it's a machine equipped with a rotary pump, it's very unlikely it's the OPV. Another possible culprit is the pre-infusion valve of the E61. But without a video - no music please and try capturing as much of the noise coming from the machine as possible - it's all currently very vague.


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## rogher (Nov 22, 2020)

squealing

hope this works (?)


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## MediumRoastSteam (Jul 7, 2015)

rogher said:


> squealing
> 
> hope this works (?)


 It does work, thank you! It's a rotary pump as well. What pressure do you have on the gauge? Does it fluctuate much? Is water entering the drip tray while you back flush or pull a shot?

Next video (unless someone knows exactly what this is 🙂 ) Backflush the machine with water, focus the video on the manometer on the right hand side and on the venting outlet (centre of the machine immediately above the drip tray, where sometimes water comes out when the machine is warming up). Thank you.


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## DavecUK (Aug 6, 2013)

*How old *is the machine, *does the brew pressure needle vibrate/flicker*?

It only seems to happen once pressure is built up, so it may be the balanced bypass..*Is it plumbed in*? *Do you have a pressure regulator if it is plumbed?*

Has anything changed to make it start doing that (e.g. moving from tanked to plumbed)

*Is water flooding into the drip tray when you pull a shot against a blind filter *(or flooding back to the tank).?


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## rogher (Nov 22, 2020)

Water floods into the drip tray when backflushing. The head pressure during backflush rises from 9bar to about 13bar.

Water also drips into the drip tray as the noise is made when pulling a shot.

The machine is plumbed. the supply line has a pressure reducer and filter in line. It's always been this way.


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## DavecUK (Aug 6, 2013)

It's meant to gush into the tray (from where exactly?) when you lower the lever. Pressure rising to 13 bar is due to water expansion and probably the balanced bypass is set to 10.5 bar ish. The drips are from where exactly? When you say a pressure reducer, what's the input pressure from the rising main set to?

Sorry to ask so many questions...I'll ask again as you may not have seen the question, *how old is the machine?*

I'm asking all these questions as you really don't want to buy a new pump if one is not required.....


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## rogher (Nov 22, 2020)

video of backflush


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## rogher (Nov 22, 2020)

The machine about three years old (cannot remember exactly) but has only been used at week-ends until recently (now daily) so I don't expect anything to be suffering from wear.

The water exits from an outlet in the centre, at the edge of the drip tray, not from the brew head. I hope the last video shows...


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## NewboyUK (Jul 14, 2018)

Is that right side gauge accurate? With the water turned off and pressure bled out does it go to zero?

To me it sounds/looks like overpressure from the pump pushing through the OPV.

Others on here are far more experienced than me but I'd like to see the outcome of this one


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## MediumRoastSteam (Jul 7, 2015)

Thanks. At a guess, @DavecUK is on the right track. - @rogher

I owned one of those machines before, and it shouldn't be doing this. The rotary pump pressure is too high, and I think it's forcing the OPV (expansion valve) to open and drain to the drip tray.

I'm assuming the pressure has never been this high before, right? It should be around 9 bar.

I think you can adjust the pump pressure quite easily. Try and adjust the pump pressure (NOT THE OPV - Leave that alone) back to 9 bar and see if the noise goes away. Failing that, I defer to Dave's knowledge. 🙂

Here it is (video)... This is EXACTLY the problem you have. 👍👍

EDIT: Disclaimer: I searched for the video AFTER typing the above. 😉


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## DavecUK (Aug 6, 2013)

The last video shows perfectly the problem...your pump pressure is far too high, reduce to 9.5 bar (you do this on an adjuster on the pump). The flow from the expansion valve outlet into the tray should stop and the noise as well.

If the flow still continues at 9.5 bar:



raise the pressure on the *pump* to 11 bar and adjust the expansion valve so the flow just stops


increase the *pump* pressure to 12 bar and ensure you get some flow from the expansion valve


finally, reduce the *pump* pressure to 9.5 bar.


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## NewboyUK (Jul 14, 2018)

DavecUK said:


> The last video shows perfectly the problem...your pump pressure is far too high, reduce to 9.5 bar (you do this on an adjuster on the pump). The flow from the expansion valve outlet into the tray should stop and the noise as well.
> 
> If the flow still continues at 9.5 bar:
> 
> ...


 Quick question - slight hijack - if you set to 9.5 then when coffee is in it goes up to 10? So set to 8.5 so goes up to 9?

Or is my thinking wrong or is that a seperate problem?


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## DavecUK (Aug 6, 2013)

NewboyUK said:


> Quick question - slight hijack - if you set to 9.5 then when coffee is in it goes up to 10? So set to 8.5 so goes up to 9?
> 
> Or is my thinking wrong or is that a seperate problem?


 Wrong thinking, you're not accounting for water expansion on heating.


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## rogher (Nov 22, 2020)

> 8 hours ago, MediumRoastSteam said:
> 
> Thanks. At a guess, @DavecUK is on the right track. - @rogher
> 
> ...


 What you say makes a lot of sense, although I'm not sure how the pump pressure could have moved so much.

Now I'll have to see if I can make that adjustment!


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## MediumRoastSteam (Jul 7, 2015)

rogher said:


> What you say makes a lot of sense, although I'm not sure how the pump pressure could have moved so much.
> 
> Now I'll have to see if I can make that adjustment!


 I'm sure you can! Good luck!


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## DavecUK (Aug 6, 2013)

Balanced bypass might be sticking due to scale...or it might be fecked (highly technical term)


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## rogher (Nov 22, 2020)

DavecUK said:


> Balanced bypass might be sticking due to scale...or it might be fecked (highly technical term)


 Since I have persuaded myself that it was an attempted de-scale that started this, I tend to think that the bypass might be the culprit (is the bypass the same thing/control that I need to adjust?). I've not paid much attention to the pump pressure but think it may have been increasing steadily (I think it was rising to 12bar but, if the OPV doesn't cut in until 12.5bar, without any noise.

If playing with the pump pressure adjustment (once I've found it) doesn't produce a result, I'll research "fecked bypass"...

I assume the bypass is supposed to limit pump pressure by relieving excess back to the boiler?


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## DavecUK (Aug 6, 2013)

rogher said:


> I assume the bypass is supposed to limit pump pressure by relieving excess back to the boiler?


 No, the bypass redirects excess pressure water back to the inlet of the pump. I have placed a .pdf of a procon pump here, the FOT pump is pretty much exactly the same.

View attachment 66097264-57fa-4382-af62-38b3ee4d68ac.pdf


Could be a lump of scale jamming it, it's really important to use good water in espresso machines. I use an Osmio Zero to avoid problems.


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## NewboyUK (Jul 14, 2018)

On machines I repair the plastic part in the deepest part gets stuck. A pull apart and clean gets them going again.... For how long is anybodys guess.

You can tell this by no matter what adjustments yoy make the pressure stays the same


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## rogher (Nov 22, 2020)

I have slept on this (not very comfortable!) and think I may have 'lied' a little bit in my earlier posts. Documenting my thoughts has also managed to jog my failing memory.

I remember that I did use the machine's reservoir to start with, before plumbing it in (kitchen re-furb).

I think the brew head pressure started off around 9 bar and may have risen to around 12 over time. I tend to regard the dials as ornamental as they're not the easiest to see with cups and hands in the way and when concentrating on other things...

I did think that my de-scaling effort was to blame, but then I remembered that I did so around the same time as I plumbed it in. I switched it back to reservoir fill and tried it again. The pump pressure rose to 12bar, without a PF, so I think that suggests the plumbing-in activity was not to blame.

Is the pump placed after the boiler (I have assumed so)? If not, de-scaling would not cause scale to get to it. I did, however, use descaling tablets in the reservoir and there may have been a deposit left behind that found its way inside. Another error that I may have made is that, when de-scaling, I passed the treated water out through the group head. I have checked the group head and it is clean, without any suggestion of blockage or deposit.

I have tried adjusting the pump pressure according to the video. This is the only adjustment that is user-accessible (I had thought it adjusted the OPV) but there is no mention of its purpose in the user manual. The video was extremely useful, thanks! I have unscrewed the brass nut by six full turns (any more and I fear it may drop out) but the pump pressure stubbornly remains at 12bar (without PF attached). There is no noise at 12bar but that is way above the 9bar I should be able to reduce it to(?)


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## MediumRoastSteam (Jul 7, 2015)

rogher said:


> ! I have unscrewed the brass nut by six full turns


 Have you tried screwing the brass nut in instead? Try that, and see if the pressure drops.


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## rogher (Nov 22, 2020)

MediumRoastSteam said:


> Have you tried screwing the brass nut in instead? Try that, and see if the pressure drops.


 Yes - but it would only screw in three full turns to the end stop. The brew head pressure remained the same: 12 bar.

I assumed that, by releasing the screw, it would reduce the pressure on a spring and hence pump pressure.


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## MediumRoastSteam (Jul 7, 2015)

rogher said:


> Yes - but it would only screw in three full turns to the end stop. The brew head pressure remained the same: 12 bar.
> 
> I assumed that, by releasing the screw, it would reduce the pressure on a spring and hence pump pressure.


 Maybe, I don't know. Ultimately, if tightening or losing the nut doesn't change anything, something is not working and needs fixing. I leave this one to @DavecUK.


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## NewboyUK (Jul 14, 2018)

To me that says that plastic part is stuck from the links DavecUK posted Strip it and clean it all - flush through - and try again.


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## rogher (Nov 22, 2020)

NewboyUK said:


> To me that says that plastic part is stuck from the links DavecUK posted Strip it and clean it all - flush through - and try again.


 I'm not sure which plastic part that is, though. The only plastic part I found was the 'lock nut' around the adjustment screw for the pump pressure. I was, at first encouraged that the pump pressure may have 'adjusted itself' when I found that but (as described) turning the screw in either direction appears to have no effect. If I took that off, I'm not sure that there'd be anything else to remove or clean.


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## NewboyUK (Jul 14, 2018)

Which of the pumps donyou have from @DavecUKlinks do you have?


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## NewboyUK (Jul 14, 2018)

See the relief valve and spring assembly? All ofnthis should come out I believe


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## rogher (Nov 22, 2020)

Ah, thanks for that. But I'm still a little confused.

Is this the screw I have been fiddling with, that pokes out underneath the machine? I thought the "Acorn Nut" would be a dome nut, but if it's been changed to a locking nut on my implementation, that would start to make more sense.

Should I simply undo the pressure adjusting screw completely, then?


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## NewboyUK (Jul 14, 2018)

The dome nut is also a locking nut too.

Turn the water off and personally i would take the hoses off and undo the pump head from the pump if possible (you have not told us which pump you have from @DavecUK list yet) so it's in your hands.

Then i would spin the shaft to see if its tight at all in places. Then remove the locknut and the adjustment shaft, spring and then the relief valve. Clean it all up and see if the valve is stuck (sounds like it is) and then reassemble.

You may be able to do it without removing the pump head but im unsure how much space you have. If theres enough space then leave it in.

All this again is just my opinion but to me it seems a lot of the pump heads I have seen are similar as to how they work.

Ill get a pump head out tomorrow are take a pic of it all apart if you like so you can see in real life more than a pic


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## rogher (Nov 22, 2020)

NewboyUK said:


> The dome nut is also a locking nut too.
> 
> Turn the water off and personally i would take the hoses off and undo the pump head from the pump if possible (you have not told us which pump you have from @DavecUK list yet) so it's in your hands.
> 
> ...


 Thanks for your support and offer of assistance.

Let me see if I can get inside and answer your questions about the pump before you go to so much trouble. Then you may have more useful information to go on.

My machine is a Rocket Cellini Evolutzione V2. At a guess, 4 or 5 years old. S/N ########£


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## NewboyUK (Jul 14, 2018)

Does it look like this?


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## rogher (Nov 22, 2020)

NewboyUK said:


> The dome nut is also a locking nut too.
> 
> Turn the water off and personally i would take the hoses off and undo the pump head from the pump if possible (you have not told us which pump you have from @DavecUK list yet) so it's in your hands.
> 
> ...


 Thanks for your support and offer of assistance.

Let me see if I can get inside and answer your questions about the pump before you go to so much trouble. Then you may have more useful information to go on.

My machine is a Rocket Cellini Evolutzione V2. At a guess, 4 or 5 years old.


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## NewboyUK (Jul 14, 2018)

Take serial off like @DavecUKsays!!


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## rogher (Nov 22, 2020)

NewboyUK said:


> Does it look like this?
> 
> View attachment 48739


 I'm not used to this forum's format & think I left my previous post unsubmitted. So I'm sorry if I had appeared to be slow or uninterested.

I've not taken the covers off my machine yet but - Yes - the bit I can see sticking out underneath looks very much like that on the LHS of the photo you've just posted. The rest is hidden within the bowels of the machine.

If I unscrew the adjustment screw completely, I'd expect to get a spring dropping out (maybe some water, too?). Is it the relief valve that's plastic and can get stuck? If that doesn't drop out, what is the best way to coax it? Do I need to unscrew the housing into which the adjustment screw screws, instead? I'm not sure if my model is like that (the drawing posted earlier doesn't show such a part, so I assume it's slightly different).


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## NewboyUK (Jul 14, 2018)

This is very similar to what you have. Undo the large nut leaving the screw in place but wound out to take pressure off the spring inside. The spring shouldn't ping off and never to be found again. On this particular pump the orange plastic part with the black o ring is the bit that sticks.

On yours I think it will be a similar design but different colours but thats by the by.

That orange bit in my case should locate in the hole of the dome you just removed and slide in/out easily. If this part is stuck inside the domed bit then that is probably your issue


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## rogher (Nov 22, 2020)

Well, I have managed to remove the above pieces from my pump-head. They all came out fairly easily from underneath (my piece was all black).

I took it out and cleaned it under a tap, although there was no obvious deposit on it, then slipped it back into the sleeve (rightmost part in the photo) and it seemed to slide in there quite happily.

However (didn't you half-expect that word?) it seems to have made no difference at all! The pressure still rises to 12.5 bar, wherever the adjustment screw is set. The pump runs sweetly when filling the boiler and the OPV only operates (squeals) when pressurising the brew head.

I'm now looking for a schematic showing the flow path from pump to brew head to better understand where a restriction might cause the pressure to rise.


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## NewboyUK (Jul 14, 2018)

When its cold and the water it turned off - does the gauge goto zero when you depressurise it? Just to see if the guage is out.

Its a machine im not familiar with but manuals are online so ill have a peek


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## rogher (Nov 22, 2020)

Yes, both gauges go to zero when off.


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## DavecUK (Aug 6, 2013)

If the pressure is going up to 12.5 bar, the balanced bypass is not working....


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## NewboyUK (Jul 14, 2018)

New pump head time?


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## rogher (Nov 22, 2020)

Is the balanced by-pass is the bit I've just been fiddling with (it would seem so)? It would seem that the operational component is that little 'plastic' bit (the relief valve). I'll need to strip it down and take a closer look... If I have the strainer bit on mine, maybe that's got choked-up.

Anyways, it seems that the problem is not likely to be beyond the pump (pump head) from what you're saying...


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## DavecUK (Aug 6, 2013)

The problem as you have surmised is in the pump itself, specifically the balanced bypass jamming or sticky.


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## rogher (Nov 22, 2020)

Having slept on this again (not getting much at the moment), I agree.

The pump must be producing too much pressure.

I'll have another look at the bypass valve. It may be that the O-ring has swollen and does not slip enough. Sadly, there were no visible signs of malfunction but then my sight or knowledge of how the thing was supposed to work could be better.

If I can't get it to work, i'll get myself a new one (machine, not pump head).


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