EBay Musica - buyers remorse? - Page 2

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
vas
Posts: 70
Joined: 2 years ago

#11: Post by vas »

There's a possible issue with a check valve that potentially can depressurize the HX loop when the boiler fill kicks in.

WWWired
Posts: 352
Joined: 5 years ago

#12: Post by WWWired »

Hi North Man Coffee :) The Musica is a brilliant espresso machine, top quality and once you've mastered cooling flushes (if you want to do them) you'll get the full experience of one of the best espresso machines ever made. You got an amazing deal on that machine! :)

Your video demonstrates a fully functional and non-leaking HX-Loop/Brew Hydraulic Pathway with an intact Steam-Boiler/HX-Loop interface and functioning one-way check valve.

When you press the Extraction button water flow/pressure is strong showing your pump is functioning well and there is no persistent air-leak anywhere in the system or in the Steam-Boiler/HX-Loop interface. As vas mentioned above, that one-way check valve can be an important location to inspect when doing annual/biennial maintenance checkups (looking for any mineral scale buildups/debris in the check-valve).

As soon as the water/extraction is called, the 3-way Solenoid (attached to the right side of the Grouphead in the Musica/Oscars) will open and that will let the World's Atmosphere be shared with your HX-Loop. Because water boils/produces-heated-water-vapor at 100℃ and 1 BAR (World's Atmospheric Pressure) it is important to be aware that a cooling flush will turn what is normally a Fixed-Volume-Pressure-Vessel, into the equivalent of a pot of water being heated up to boil an egg. As soon as the 3-way Solenoid is opened (without a portafilter/coffee powder in place), the pressure in your HX Loop will be equalized with the World's Atmosphere (1 BAR) and you may experience some steam/heated-water-vapor production in the highest parts of your HX Loop. This can create a Steam-Blockage/Thermosiphon-Loop-Stall until the pressure can build again (when 3-way Solenoid is de-energized). The flash-boil/water-vapor-production internally can be witnessed perfectly in your video when you are doing the cooling flush . . . the initial Grouphead water flow/pressure is great, then, as the Pressure in the HX Loop/Brew Path is equalized to the World's Atmospheric Pressure, there appears to be some Steam/Heated-Water-Vapor production somewhere in the Brew Pathway creating a Vapor-Lock/Blockage as water flow from the Grouphead stalls. Towards the end of the supplied video, the water flow does sputter/intermittently begin to improve as the pump pressure influenced water pressure fluctuates against the vapor lock/thermolock to increase pressure behind the lock in an attempt to push through it.

Its important to remember that Air Pressure can increase well above water pressure in some phases/temperatures/pressures. The situation of a Thermosiphon/HX-Loop steam-vapor-lock is one of those weird Twilight Zone regions, that with a bit of practice and awareness, can skillfully be controlled while cooling the Grouphead Assembly just prior to an extraction. If some boiling/steam production can develop during a cooling flush, this may create an Air-Lock/Block and stall water flow in the Brew Pathway. This is odd, because the Steam-Boiler's pressure is often much lower than Pump influenced Brew Pathway Resistance/Pressure (9+ BAR), so the conclusion is it is not higher pressure air blocking the Brew Pathway Water (1.2 to 1.5 BAR matching the Max of the Steam Boiler), but rather just the inability of the Brew Water Pressure in the HX Loop to increase due to exposure to the much lower 1 BAR world's atmosphere constantly shot-blocking the pump's attempts to increase the pressure/resistance in the Brew Pathway/HX-Loop . . . therefore the steam pressure wins and creates a Thermoloop-block intermittently as the Pressure behind the Vapor/Steam Lock fluctuates under the influence of the pump. Vas's link above directs to some brilliant posts by HB that discuss cooling flush theory and practices. The design of these machines is meant to hit brew temperature marks of approximately 88℃ leaving the Grouphead/coffee-power-puck and 67℃ in the Cup. If these temperatures are being exceeded, the cooling flush may assist in addressing the issue, but the trick is to not expose the Thermosiphon/HX-Loop too long to the World's much lower atmosphere of 1 BAR where boiling eggs and spaghetti works incredibly well ;) And remember that just because 88 is the temp leaving the Portafilter into the cup, taking you Back-to-the-Future, doesn't mean that your Mr-Fusion-Krupps-Coffee-Grinder-HX-powered Thermosiphon Loop is also running at 88℃, and it will more likely be capable of boiling water (100℃) all the time but for the fact that the HX/Brew hydraulic pathway is a Fixed-Volume-Pressure-Vessel that is constantly under-pressure and not open to the GIGANTIC world's 1 BAR Atmosphere (which happens when doing a cooling flush without a portafilter in place).


Here's a model of the Nuova Simonelli/Musica class of boiler (with some fitting differences between machine models) for anyone who wants to click around the model and check out how the HX Loop inside the Boiler is oriented (hopefully this is not a horrible model haha, I'm thinking about further cleaning up the model and adding more NS model variant, musica/oscar I/oscar II, components perhaps) . . .
Sketchup Oscar/Musica Boiler-HX Loop

lukeap69
Posts: 81
Joined: 11 years ago

#13: Post by lukeap69 »

Check if the preinfusion is ON.
I used a Musica for many years and I made some of my best coffee with it.

mangoie
Posts: 68
Joined: 2 years ago

#14: Post by mangoie »

I also have a musica from around the same build year. Indeed doesn't look normal, already when the water starts to exit the group head its way to aggressive, so maybe it's pushed out by the steam?

Indeed what baristaboy says I would start with a full descale. It's cheap and easy to do, just takes some time.

I'm also not an expert on these (or any E61 style) machines, but what comes to mind:
-steam means too much energy per water unit. So maybe the boiler too hot?
-maybe too little water per second pumped in by the ULKA pump?
-losing somewhere water pressure?

North Man Coffee (original poster)
Posts: 6
Joined: 3 months ago

#15: Post by North Man Coffee (original poster) »

Hello there,

What a fantastic message, thank you so much for taking the time to to write it.

Very interesting and reassuring to read that, and I have been doing lots of testing today - when I can, we have a new 14 week old darling girl to take of so she of takes up the majority of what I used to call free time.

I have found that by opening the steam wand for around 3 seconds and a good group flush, I've been able to get much better shots today which has been a huge relief.


As others have touched on, I think the pre-infusion settings may need attention to as several of the buttons seem to behave strangely. I have to hold the hot water tap and the power button to turn it off for instance, and the power button, when pressed, triggers the hot water tap :lol:

I did also do a descale today, only used citric acid so I'm not sure whether something stronger may be needed but it can't hurt. Put one tbsp into a liter and ran that through, followed by a litre of fresh to cleanse. I did message our local espresso engineer to book the machine in for a service and once over so hopefully they'll be able to cure any minor ailments!

Thanks again everyone, wonderful welcome to the forum :D

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BaristaBoy E61
Posts: 3548
Joined: 9 years ago

#16: Post by BaristaBoy E61 »

North Man Coffee wrote:Very interesting and reassuring to read that, and I have been doing lots of testing today - when I can, we have a new 14 week old darling girl to take of so she of takes up the majority of what I used to call free time.

I have found that by opening the steam wand for around 3 seconds and a good group flush, I've been able to get much better shots today which has been a huge relief.
Congrats on the new addition to the family!

Maybe the anti-vac valve needs a good cleaning.

Enjoy your family!
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

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TheCatsMeow
Posts: 48
Joined: 6 months ago

#17: Post by TheCatsMeow »

vas wrote:That's because the overheated water from the boiler part of HX loop escaped as steam and any new water coming in turns to steam instantly.

idk, maybe this thread can explain what's going on better.
-Scrubbing this comment, not sure if any of it was right- Going to leave this one to those that know more lol

Jonk
Posts: 2219
Joined: 4 years ago

#18: Post by Jonk »

North Man Coffee wrote:I did also do a descale today, only used citric acid so I'm not sure whether something stronger may be needed but it can't hurt.
It can hurt, if the boiler fill kicks in and leaves citric acid in the steam boiler. It's been awhile but IIRC it has a valve by the bottom side of the boiler you can open to drain any descale solution (some other HX machines would drain through the hot water tap when tilted, but this won't work with the Musica as it's actually pumping fresh water from the HX to that tap).

Steam is normal, mine looked pretty much like this:
(flush until you get a proper stream of water before turning off and locking in the portafilter to pull a shot right away, about 15s in the video)

If you lower steam boiler pressure (adjust the pstat carefully, it's probably glued in place) you'll get less of this sputtering behaviour. 1.1 bar or so is still plenty.

So there might be something off with your machine, but I do remember mine acting a bit weird like that when not actually brewing coffee. If the flow seems fine when you pull a shot (after a cooling flush) perhaps there is no issue, just NS oddity :mrgreen:

mangoie
Posts: 68
Joined: 2 years ago

#19: Post by mangoie »

(Older) Musica's have as a default that when a shot starts the hx tube fills first, and than after a few seconds a solenoid opens so the water goes to the group. Yours has this disabled so I think you video is not a good representation how it should look like...

This is mine from 2013

North Man Coffee (original poster)
Posts: 6
Joined: 3 months ago

#20: Post by North Man Coffee (original poster) »

Hello everyone,

Just an update; got the machine back from the local spanner and got a clearer idea of its issues now.

The flow meter was found to be defective and I'm not a fan of volumetrics we went for the cheap fix of bypassing it, the flow is now much improved and I can make a decent shot.

Also found was two missing gigleurs (I'm saying that in the hope you know what they are!), some small areas of corrosion, a nick in the ribbon cable causing the strange button operations and the OPV had been set to 5 bars.

All in all, £60 was spent and I'm now using the machine quite happily so I think the buyers remorse has passed! :)