# Help Diagnose a Problem



## chip_kara (Sep 25, 2017)

So I'm having a few problems with my Classic which was bought on here a couple of weeks ago from @osrix . Its a 2012 model with a PID (currently set at 100C) and OPV set to 9 bar to provide some details.

It's been working a treat, pulling tasty and also good looking shots ever since arriving until the last few days when I can't seem to get anything drinkable from it using two different coffees. With those coffees I've adjusted the grind on the Mignon while keeping the same dose of 18g but I've adjusted more than I ever remember having to previously on the classic or cubika but it is making very little difference to the shot.

I've descaled, backflushed and completely cleaned the dispersion plate/shower screen etc. and everything is clean/clear.

My shots yesterday/today with some HasBean which was roasted on the 15th seemed to be almost choking the machine on the grind setting it had been working on fine before - despite changing the grind significantly more than I have had to before I couldn't get anything drinkable and ran out of beans suitably beyond their roast date trying.

I picked up a bag of Dark Woods Aboretum Espresso in town which I've had before and know is nice. This was roasted on the 19th Feb. I pulled several shots tonight and how ever much I vary the grind the shot begins almost like its going to be a good shot but then instead of forming one nice central stream starts fizzling/bubbling/foaming and the result is pretty grim with no good crema.

I am now left pondering whether the coffee is to blame(seems unlikely?) or whether its the machine and if so what.

I was wondering if its something to do with the water flow? I have noticed once or twice that the tone of the pump seems to change and the flow rate changes as well.

There is still a decent looking shower of water through the shower plate so didn't think it was the solenoid but am probably wrong, would timing and measuring water output help?

Any advice would be greatly appreciated as I'm tired of wasting coffee!

Thanks









* Link for water flow below *


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## rob177palmer (Feb 14, 2017)

chip_kara said:


> the shot begins almost like its going to be a good shot but then instead of forming one nice central stream starts fizzling/bubbling/foaming and the result is pretty grim with no good crema.
> 
> )


To me, that sounds like channelling.

When you remove the PF, are there noticeable pinpoint dips in the puck surface?

Check your distribution technique. Seems strange that this would have changed enough to significantly effect the extraction, but smooth flow changing to spurting is usually channelling.


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## chip_kara (Sep 25, 2017)

I've changed absolutely nothing in my technique, still weigh, grind into steel pot, shake, transfer to pf, stir, tamp. I'm sure its not perfect but I am pretty sure I'm at least consistent so didn't think that would have such a drastic effect?

No noticeable points on the puck surface, just a very slight imprint of the IMS screen.


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## rob177palmer (Feb 14, 2017)

Are you certain there aren't any of these telltale signs?

http:// https://www.google.co.uk/search?q=portafilter+puck+channeling&client=safari&hl=en-gb&prmd=sivn&source=lnms&tbm=isch&sa=X&ved=0ahUKEwip_Om3zcnZAhWmKcAKHQZDCzsQ_AUIEigC&biw=375&bih=553#imgrc=AOOVehn8A2SOAM:


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## rob177palmer (Feb 14, 2017)

You say the pump changes noise - is that when the puck is in place (this would be normal as the pump starts to labour ) or without?


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## chip_kara (Sep 25, 2017)

Pretty sure! Plus what are the chances I could suddenly cause that change on the 8 shots or so I've tried today.


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## rob177palmer (Feb 14, 2017)

TBH, annoyingly high chance! It has happened to me and taken ages to diagnose and get back to a proper prep routine on my Classic


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## chip_kara (Sep 25, 2017)

rob177palmer said:


> You say the pump changes noise - is that when the puck is in place (this would be normal as the pump starts to labour ) or without?


I've noticed this when the filled pf is not in place and have a video of the bare shower screen while it happens from a couple of days if I can think how to share the vid.


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## rob177palmer (Feb 14, 2017)

But obviously this might not be the problem - study the puck next time you try. Also try on a naked PF if possible? That will really help you spot if channeling is the issue


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## rob177palmer (Feb 14, 2017)

chip_kara said:


> I've noticed this when the filled pf is not in place and have a video of the bare shower screen while it happens from a couple of days if I can think how to share the vid.


Do share - that will help. Pumps are cheap and easy to replace if needed


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## chip_kara (Sep 25, 2017)

rob177palmer said:


> But obviously this might not be the problem - study the puck next time you try. Also try on a naked PF if possible? That will really help you spot if channeling is the issue


All the shots have been pulled using a naked pf, only ever use a naked PF!


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## chip_kara (Sep 25, 2017)

Hopefully that link should work to the video of the water flow/pump noise


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## Jollybean (May 19, 2013)

Try dropping the dose to 17g to see if you need some more headroom in the portafilter.


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## chip_kara (Sep 25, 2017)

Jollybean said:


> Try dropping the dose to 17g to see if you need some more headroom in the portafilter.


Hmm good suggestion, I'll try that tomorrow morning


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## rob177palmer (Feb 14, 2017)

chip_kara said:


>


Ah, Okay - that does look like water flow is causing the issue.

So the pump starts to labour and the flow slows down. You then turn off the pump and start again, so the pump fires at full power again. If you were to do all that with a puck in there then you would fracture the puck and get huge channelling and a spurter. Seems like this explains the issues.

So how to solve it!!?? I never had that issue, so can't say for sure, but to me that seems to be either blocked tubes somewhere or needing to replace the pump.

You say you descaled recently - there could be loose scale floating around in there and occasionally blocking the water path.

Without the PF in place, time how long before the pump labours and the flow reduces, then let it rest. Repeat this a few times. If the time taken is almost identical each time it would be strange to be a piece of scale randomly blocking tubes, so this might indicate a new pump needed.

Let us know, but if that waterflow video repeats every time you try to brew, it is no wonder you are getting shocking shots!


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## chip_kara (Sep 25, 2017)

I had thought that it might just be loose scale but it seemed too consistent a problem especially after two descales. I'll try the timing thing and see.

Do you know if there are any guideline figures on how much water should pump out in a specific time? Or whether this is even a valid thing to measure.

What I wondered was if the pump is struggling simply without the PF in place, what does it do when its in place and under pressure!


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## El carajillo (Mar 16, 2013)

I think you have a particle of scale floating about and blocking the solenoid, if it is d/scaling will not clear it, you will need to remove and dismantle / clean the solenoid valve.

The fact that the pump is struggling would also suggest solenoid problem as the water passes through the solenoid to the brew head.

Are you sure there is no air in the feed to the pump and no crushed or kinked hose?


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## rob177palmer (Feb 14, 2017)

Agree with El Carajillo - if timing shows the labouring occurs irregularly then it will be lose scale / crud inside the machine and a clear out / full dismantle should help. It's a fairly regular issue on the Classic but totally fixable.


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## Jumbo Ratty (Jan 12, 2015)

Just check that the water tubes going into the water reservoir have not become kinked.


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## osrix (Feb 15, 2013)

Just caught up on this. after watching the last video, it doesnt sound like the pump is failing. I had a similar issue with a machine someone gave me to repair. In this case It was a tiny seed stuck in either the solenoid or the opv i cant remember which now. but exact same symptoms. Starts off fine then laboring to almost stop on that one.

My advice would be to start with the opv as its the easiest and flush it and then move onto the solenoid if need be. I would be very surprised if it wasnt as scale or some other foreign body that has found its way to a pinch point..i'm trying hard to remember, but i think inside the Opv is a small jet 1mm or so maybe less which is where the seed above was found.


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## chip_kara (Sep 25, 2017)

Thanks for all the advice guys. No kinks or air in the hoses running into the tank.

I've done another video this morning, link below, three clips from this morn edited together.

1st clip - First time pump was on this morning after heating up for about 5/10mins

2nd clip - Similar to other vid where water flow looks fine but then labours.

3rd clip - Shows slow flow then pump noise change and fast flow again.






I will try and take a look at the OPV and Solenoid this afternoon. What you've suggest Ben sounds like the likely cause. I've got a dissertation and two essays due in the next 28 days so trying not to just spend the day taking my machine apart but it's hard to resist!


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## rob177palmer (Feb 14, 2017)

I'm with you - I know which I'd be focusing on









How can you be expected to achieve greatness without your caffeine fix??


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## chip_kara (Sep 25, 2017)

rob177palmer said:


> I'm with you - I know which I'd be focusing on
> 
> 
> 
> ...


Is it a suitable enough excuse to apply for an extension I wonder...


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## El carajillo (Mar 16, 2013)

It will be the solenoid valve as the OPV would not reduce pressure at brew head by choking.


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## osrix (Feb 15, 2013)

El carajillo said:


> It will be the solenoid valve as the OPV would not reduce pressure at brew head by choking.


But it could reduce water flow surely?


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## El carajillo (Mar 16, 2013)

osrix said:


> But it could reduce water flow surely?


If it was stuck in the open position it could reduce the flow to the group head =lack of pressure . If this were the problem the pump would not be struggling and you would see the water returning to the tank.

If it was blocked the water would be forced through the brew head which is not happening.


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## chip_kara (Sep 25, 2017)

Maybe it is the Solenoid after all then, if I have time tonight I'll take it out and give it a clean and see whats what.


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## Missy (Mar 9, 2016)

chip_kara said:


> Maybe it is the Solenoid after all then, if I have time tonight I'll take it out and give it a clean and see whats what.


It's *always* the solenoid


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## chip_kara (Sep 25, 2017)

Missy said:


> It's *always* the solenoid


So it seems, the labouring pump noise threw me off at first, hopefully it will return to normal after some tinkering.


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## chip_kara (Sep 25, 2017)

Right, so after finishing some work I went at the classic.

I removed the Solenoid stripped it down, cleaned it (surprised how clean it was) and put it back together and back on the machine and as far as I can see from pulling some water through its made no difference.

The flow still changes and the pump tone changes and seems to be labouring.

One thing I did do was fill a jug for the input for the pump and placed the output into a separate jug, I then ran the pump for around 45seconds across which time the flow changed, however at no point did any water flow through the output and the jug remained bone dry.

Does this indicate anything more specific?

I just really want to be able to use the machine now!


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## El carajillo (Mar 16, 2013)

From your post you can rule out the OPV. You did split the S /valve into its component parts, not just remove solenoid ? just checking.

Remove shower screen and dispersion block (2 allen screws) then try M/ch. This should rule out any crud in brew head.

Other thoughts, possible larger flake of scale in the outlet from the boiler to the S/valve OR broken spring in the pump reducing effective pumping pressure

Free flow rate from the pump should be about 125 -130 cc in 30 sec depending on which pump is fitted E4 or E5


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## chip_kara (Sep 25, 2017)

El carajillo said:


> From your post you can rule out the OPV. You did split the S /valve into its component parts, not just remove solenoid ? just checking.
> 
> Remove shower screen and dispersion block (2 allen screws) then try M/ch. This should rule out any crud in brew head.
> 
> ...


Yep I stripped the valve down completely did not just remove the solenoid.

I did the shower screen/dispersion block before starting this thread, I cleaned it all up and there was no sigh of crud/blockages in the brew head. - but I could have another look considering the ease.

Would it be worth descaling it again but leaving the solution sitting in the machine for a while?

It doesn't seem like the pumps are too hard to strip down so I could give that a go?


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## El carajillo (Mar 16, 2013)

For ease it would be worth another D/scale. The pumps are "easy" to strip down, check all components and look at the large coil spring.

When I stripped mine, what I initially thought was a circlip turned out to be one coil of the spring broken off. It was still pumping but a new pump showed the difference.


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## chip_kara (Sep 25, 2017)

I'll give that a go later then as I've got a fair few of Puly descaler sachets and I'll leave it sitting the machine a while.

I'll try and find some time to strip the pump then, hopefully that will show up as the problem.


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## chip_kara (Sep 25, 2017)

I stripped the pump down and everything seems as it should be compared to a guide online. i.e no broken springs. But fitted back on it still has the same problem even after another lengthy descale. I've ordered a new pump so hopefully that will sort it but if not at least it can be returned.


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## chip_kara (Sep 25, 2017)

Forgot to post the other day, the night that I ordered the replacement pump I was driving home from work and it suddenly occurred to me that my old cubika which was in its box in the bottom of my wardrobe probably had the same pump. Popped the pump out of the cubika and was unsurprised to find it was identical, swapped it into the classic and immediately all my problems were gone. Had it working for a few days now which have been my first to properly appreciate the new to me machine and its great.

That cubika cost £99 refurbished from Gaggia over 4 years ago and is now powering my Classic. Pretty good value for money I'd say!

Thanks for everyones help in trying to fix the issue.

p.s. the replacement pump arrived from amazon bouncing around an oversized box and was pretty damaged anyway so that filled in the return form!


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## ashcroc (Oct 28, 2016)

chip_kara said:


> Forgot to post the other day, the night that I ordered the replacement pump I was driving home from work and it suddenly occurred to me that my old cubika which was in its box in the bottom of my wardrobe probably had the same pump. Popped the pump out of the cubika and was unsurprised to find it was identical, swapped it into the classic and immediately all my problems were gone. Had it working for a few days now which have been my first to properly appreciate the new to me machine and its great.
> 
> That cubika cost £99 refurbished from Gaggia over 4 years ago and is now powering my Classic. Pretty good value for money I'd say!
> 
> ...


You've gotta love gaggia's ethos of just 'going to the shelf' to get the same parts for multiple machines.


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