# Backflush, clean out solenoid, 6-8 cups perfect then slows badly. Repeat. HELP



## mark_gaggica_classic (Jun 6, 2016)

Hello all,

I've read quite a few posts, and googled extensively.

Gaggia Classic is circa 3 years old. Every 6-8 cups I have to clean out the solenoid. The last time I managed to empty contents into a white cup. Basically getting clogged with coffee. After cleaning, it runs perfectly, but only for 3-4 days. After 2 days it starts to slow, by day 4 it is down to drips and I have to clear the solenoid again. How do I stop this?

Note I filter my water, there is zero lime scale, I have backflushed numerous times with the powder stuff. The shower curtain is cleaned. The coffee basket is clean...

I'd think I need a new solenoid, but... it works then gets blocked, works then gets blocked, so would a new solenoid really help in this instance?

Any help appreciated.

Mark


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## Pyro (Jun 28, 2014)

It's good to see you are back flushing your machine however I'm going to ask a question most will ask...

Have you descaled your machine?


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## 4085 (Nov 23, 2012)

the aim of the solenoid is to cut the water supply to the puck, and when it does this, it 'sucks' back. Probably a wildshot but I wonder if you are overfilling your basket, meaning there is not enough headroom. What size basket are you using and how much are you putting in?


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## mark_gaggica_classic (Jun 6, 2016)

Yes I have descaled it. But as I mentioned, there isn't a smidgen of limescale anywhere. I also filter my water.


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## mark_gaggica_classic (Jun 6, 2016)

It worked fine for circa two years and I've made no changes. It's the last year I've had issues. I've tried increasing the grind size (made no difference). I typically fill it to 75% full, max 85%. I also tamp (but not too hard). I did buy an upgraded basket - but can't remember what it was, but I've had it since new.


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## mark_gaggica_classic (Jun 6, 2016)

It's a full depth basket, if that helps.


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## 4085 (Nov 23, 2012)

mark_gaggica_classic said:


> It's a full depth basket, if that helps.


when you remove the pf handle, does the showerscreen leave an imprint in the puck?


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## Pyro (Jun 28, 2014)

Is the flowrate reduced with the PF handle removed?


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## Jumbo Ratty (Jan 12, 2015)

mark_gaggica_classic said:


> Yes I have descaled it. But as I mentioned, there isn't a smidgen of limescale anywhere. I also filter my water.


How regularly do you descale ?

How do you know there isnt any limescale ?

I also filter my water and used to descale every 2 months, ive now upped that to every month for my gaggia classic.


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## mark_gaggica_classic (Jun 6, 2016)

No.


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## mark_gaggica_classic (Jun 6, 2016)

I live in a soft water area. There is no limescale. Kettle doesn't fur up etc. The blockages is being caused by ground coffee, not limescale. I haven't seen even a trace of limescale however I've taken it apart... hope that helps


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## mark_gaggica_classic (Jun 6, 2016)

When I take off the solenoid, remove the ground coffee that's stuc, reassemble (I can now do in under 5 mins) the flow is very good. With or without the PF. Today, 3 days after last clean, it's back to dripping, with or without the PF. This is the cycle







(Thanks for your help)


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## Jumbo Ratty (Jan 12, 2015)

mark_gaggica_classic said:


> It worked fine for circa two years and I've made no changes. It's the last year I've had issues.


Its limescale


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## mark_gaggica_classic (Jun 6, 2016)

Jumbo Ratty said:


> Its limescale


I really appreciate your trying to help









If it's limescale why does it work after cleaning out the solenoid which ONLY has coffee granules stuck in there (see image)






? Where is this limescale? It's not in the solenoid, not in the shower head or round the area where the water comes out... I did descale about a month ago (twice) but the same happened - it was ok for up to a week then flow meant I had no choice other than to clean out solenoid again









I can do another descale. Where would it be building up? And why wouldn't it be accumulating in the solenoid?


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## urbanbumpkin (Jan 30, 2013)

Did is start doing this just after the descale?


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## urbanbumpkin (Jan 30, 2013)

Is it definitely coffee grinds, sorry I can't tell from the photo?

I have heard of anodised aluminium boilers losing part of their coating if it's descale too hard. Baby Pully is pretty good for gaggia classics.

If so it could just be this gunk that's in the bottom of the boiler that keeps coming out.

Any thought from anyone else?


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## Missy (Mar 9, 2016)

Are you cleaning before you back flush? Stuff seems to take time to work into the teeny weeny solenoid holes.


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## Pyro (Jun 28, 2014)

If you're certain it's just coffee grounds I suggest you get an IMS screen, apparently let less gunk through so may help your cause...


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## mark_gaggica_classic (Jun 6, 2016)

urbanbumpkin said:


> Did is start doing this just after the descale?


No. I did the descale (as well as a backflush with the right powder stuff) as it had almost stopped flowing.


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## mark_gaggica_classic (Jun 6, 2016)

Missy said:


> Are you cleaning before you back flush? Stuff seems to take time to work into the teeny weeny solenoid holes.


When I backflush (which is before/after cleaning solenoid), I first put the powder in the basket and run through, then brush the area where the water comes out of the head, then remove the shower screen (is that what's called?) and ensure that is completely clear with no blockages in the tiny holes, then run through with water, then finally backflush with the powder, running it for 5-10 seconds (waiting for the motor to change sound), turn off, repeat maybe 10 times, then run through with clean water. At this point flow is excellent. But then over the next 4 or so days it gets gradually slower until I need to clean out the solenoid again... cleaning the solenoid results in excellent flow each time. I've done this now 30 times?


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## timmyjj21 (May 10, 2015)

The solenoid shouldn't get coffee grinds that size in it to begin with. What does your shower screen look like? When back flushing do you get a good pressure build up that vents nicely, or is it a dribble?

A solenoid blocked from grinds in the venting pathway shouldn't show up as slow water flow when brewing. The holes should be separate and not communicate to that extent. I immediately suspected that it is repeat blockage from something that is inside the boiler, and many people commented it is probably limescale. If you are adamant that it can't be, then other alternatives might include a dodgy internal solenoid piston seal, or other junk inside the boiler.


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## mark_gaggica_classic (Jun 6, 2016)

Pyro said:


> If you're certain it's just coffee grounds I suggest you get an IMS screen, apparently let less gunk through so may help your cause...


Hi there - ok looked it up http://www.theespressoshop.co.uk/en/gb/IMS-Integrated-Shower-Plate-Gaggia-55mm/m-2010.aspx and it does look like it might do the trick. I can't understand why I get this problem to start with though - my machine was fine for so long, now I have to unblock solenoid every 3-5 days. But from the reviews http://www.gaggiausersgroup.com/index.php?topic=572.0 it does seem to stop ANY coffee granules etc going back up to the solenoid...

One question on the coffee grounds - I'm assuming that limescale would be grey/yellow rather than brown. I will have another clean and check, though I guess I should expect the limescale to be the same colour as the coffee - in which case how can I tell? Leave it in a mixture of bicarbonate of soda for a few hours and see if it dissipates?


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## 4085 (Nov 23, 2012)

limescalewill be a different colour and uneven in particle size.....in other words look nothing like coffee grinds


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## mark_gaggica_classic (Jun 6, 2016)

timmyjj21 said:


> The solenoid shouldn't get coffee grinds that size in it to begin with. What does your shower screen look like? When back flushing do you get a good pressure build up that vents nicely, or is it a dribble?
> 
> A solenoid blocked from grinds in the venting pathway shouldn't show up as slow water flow when brewing. The holes should be separate and not communicate to that extent. I immediately suspected that it is repeat blockage from something that is inside the boiler, and many people commented it is probably limescale. If you are adamant that it can't be, then other alternatives might include a dodgy internal solenoid piston seal, or other junk inside the boiler.


Hmm... Ok you clearly know what you are talking about. If it shouldn't get coffee grinds that size, and even if it did, it shouldn't stop operation then I need to look elsewhere.

When I'm cleaning (using Cafiza 2), and I backflush, yes I get a good steady stream of white bubbles/liquid, though not necessarily on the first attempt.

I clearly need to check its not limescale (again), as maybe I mistakenly thought the brown molecules were coffee, but realise it could be stained limescale. So I will do another few descalers. I'm trusting that bicarbonate of soda is good enough for this exercise?

The seal inside the metal solenoid is fine with no apparent damage?

Thanks very much for your help.


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## mark_gaggica_classic (Jun 6, 2016)

dfk41 said:


> limescalewill be a different colour and uneven in particle size.....in other words look nothing like coffee grinds


So potentially like the solids I posted in the previous photo? (If it turns out to be limescale I will eat a good slice of humble pie!)


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## mark_gaggica_classic (Jun 6, 2016)

mark_gaggica_classic said:


> So potentially like the solids I posted in the previous photo? (If it turns out to be limescale I will eat a good slice of humble pie!)


I will buy some white vinegar and do it properly - and report on the results. Thanks everyone!


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## Pyro (Jun 28, 2014)

mark_gaggica_classic said:


> Hmm... Ok you clearly know what you are talking about. If it shouldn't get coffee grinds that size, and even if it did, it shouldn't stop operation then I need to look elsewhere.
> 
> When I'm cleaning (using Cafiza 2), and I backflush, yes I get a good steady stream of white bubbles/liquid, though not necessarily on the first attempt.
> 
> ...





mark_gaggica_classic said:


> I will buy some white vinegar and do it properly - and report on the results. Thanks everyone!


Please no! Do not use vinegar on your machine there's a lot of documented arguments against the use of vinegar with the Gaggia's aluminum boiler.

Please don't use bicarbonate/baking soda either, you'll be very likely to clog the machine, I feel we've probably stumbled upon the error here...

Use a descaler intended for use in such a machine such as the highly recommended puly descaler:-

http://www.happydonkey.co.uk/hd0588-puly-baby.html


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## mark_gaggica_classic (Jun 6, 2016)

Pyro said:


> Please no! Do not use vinegar on your machine there's a lot of documented arguments against the use of vinegar with the Gaggia's aluminum boiler.
> 
> Please don't use bicarbonate/baking soda either, you'll be very likely to clog the machine, I feel we've probably stumbled upon the error here...
> 
> ...


OK THANKS! Just ordered. I've also ordered an IMS screen. I did just try a backflush after cleaning the shower head, but only with water, x 5, and the flow is far better without cleaning the solenoid too... will keep you posted. Many thanks.


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## Jumbo Ratty (Jan 12, 2015)

mark_gaggica_classic said:


> I can do another descale. Where would it be building up? And why wouldn't it be accumulating in the solenoid?


The build up of scale would be in the boiler,, descaling causes it to break up, which is why your meant to vent the descaler solution out through only the steam wand, not the brew head. (This is what is written on the actual gaggia descaler bottle)

The smallest hole in the entire water route when brewing is in the solenoid. That is where small dislodged particles of scale will accumulate and block the machine.



mark_gaggica_classic said:


> then remove the shower screen (is that what's called?) and ensure that is completely clear with no blockages in the tiny holes, then run through with water,


You make no mention of removing the dispersion plate. Do you remove the 2 allen key bolts and take off the dispersion plate and clean behind that ?



mark_gaggica_classic said:


> When I take off the solenoid, reassemble (I can now do in under 5 mins) the flow is very good.


Thats very quick. Which makes me wonder if, after the solenoid is removed from the machine, do you then take the solenoid valve to pieces?

Do you end up with the piston and spring end of the solenoid apart from the bottom part like in this photo.

Do you then stick a pin in through the top hole, the smallest hole the 1 in the center of the threaded area not surrounded with the rubber washer and really rummage around?


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## mark_gaggica_classic (Jun 6, 2016)

Jumbo Ratty said:


> The build up of scale would be in the boiler,, descaling causes it to break up, which is why your meant to vent the descaler solution out through only the steam wand, not the brew head. (This is what is written on the actual gaggia descaler bottle)
> 
> The smallest hole in the entire water route when brewing is in the solenoid. That is where small dislodged particles of scale will accumulate and block the machine.
> 
> ...


As per above I'm willing to eat humble pie on the descaling. I will follow instructions. As I mentioned I used bicarbonate of soda which is a no no. I know that now but that could what the repeated gunk is as I tried descaling by running water through the head as well as wand. I've learnt my lesson on that one.

Regarding your picture above - yep - five minutes. I've done it so many times now I have all the right tools on stand by. I pull out the solenoid, undo it, ensure the two tiny holes are running clear, ensure there is no gunk around the spring and reassemble. 5 minutes easy.

I've only taken the dispersion plate off once.

Thanks again.


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## Pyro (Jun 28, 2014)

mark_gaggica_classic said:


> As per above I'm willing to eat humble pie on the descaling. I will follow instructions. As I mentioned I used bicarbonate of soda which is a no no. I know that now but that could what the repeated gunk is as I tried descaling by running water through the head as well as wand. I've learnt my lesson on that one.
> 
> Regarding your picture above - yep - five minutes. I've done it so many times now I have all the right tools on stand by. I pull out the solenoid, undo it, ensure the two tiny holes are running clear, ensure there is no gunk around the spring and reassemble. 5 minutes easy.
> 
> ...


Your weekly cleaning should include removing the dispersion plate from the machine, it's less than 2 mins to remove and just leave it to soak in a coffee machine cleaning solution such as Puly Caff. I'm not saying this is the actual problem but not cleaning the shower screen, grouphead, dispersion plate as well as regular descaling will lead to a much poorer quality and shorter service life of your machine.


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## Jumbo Ratty (Jan 12, 2015)

Jumbo Ratty said:


> You make no mention of removing the dispersion plate. Do you remove the 2 allen key bolts and take off the dispersion plate and clean behind that ?





mark_gaggica_classic said:


> I've only taken the dispersion plate off once.





Pyro said:


> Your weekly cleaning should include removing the dispersion plate from the machine


I suggest taking the dispersion plate off and cleaning it more than you do, much more.

This harbours stale coffee behind it, and if left too long can be a bugger to get off (the dispersion plate itself, not the stale coffee.


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## urbanbumpkin (Jan 30, 2013)

Worth taking the dispersion plate off. I never did mine more than every couple of months.


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## mark_gaggica_classic (Jun 6, 2016)

Jumbo Ratty said:


> I suggest taking the dispersion plate off and cleaning it more than you do, much more.
> 
> This harbours stale coffee behind it, and if left too long can be a bugger to get off (the dispersion plate itself, not the stale coffee.


Ok - just tried to get it off. Won't budge







watched various videos on doing it to no avail. All I'm doing is marking the (aluminium?) dispersion plate in my attempts.

(and yes I've removed the two bolts with alan keys).

Anyone any ideas?


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## mark_gaggica_classic (Jun 6, 2016)

urbanbumpkin said:


> Worth taking the dispersion plate off. I never did mine more than every couple of months.


I've just learnt to my cost what not doing so means. I can't budge the damn thing - see post above.


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## Missy (Mar 9, 2016)

Try putting a screwdriver gently a hole and prising. You may need to use a flat blade round the edges too. You'll need a new gasket seal thing (only a few quid) as they go hard and crusty. You'll likely need to force that out too.


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## mark_gaggica_classic (Jun 6, 2016)

Missy said:


> Try putting a screwdriver gently a hole and prising. You may need to use a flat blade round the edges too. You'll need a new gasket seal thing (only a few quid) as they go hard and crusty. You'll likely need to force that out too.


I've tried gently. I've tried hard. I've tried twisting by using short handled plyers. I've tried light tapping, slightly harder tapping.. but as I say, all I'm succeeding doing is marking the head itself









Currently soaking in cleaner see if that helps...

Any other ideas?


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## mark_gaggica_classic (Jun 6, 2016)

mark_gaggica_classic said:


> I've tried gently. I've tried hard. I've tried twisting by using short handled plyers. I've tried light tapping, slightly harder tapping.. but as I say, all I'm succeeding doing is marking the head itself
> 
> 
> 
> ...


Soaking it in cleaner solution loosened it - thanks everyone







))


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## urbanbumpkin (Jan 30, 2013)

If it's stuck on this badly, maybe this could be the root cause of the blockages. Soak it in Pulcaff, then clean up with something like fairy power spray as the aluminium block will darken from the pulcaff/coffee oil cleaner.


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## Missy (Mar 9, 2016)

And replace the rubber gasket, which I'm presuming you've taken out.


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## mark_gaggica_classic (Jun 6, 2016)

urbanbumpkin said:


> If it's stuck on this badly, maybe this could be the root cause of the blockages. Soak it in Pulcaff, then clean up with something like fairy power spray as the aluminium block will darken from the pulcaff/coffee oil cleaner.


I reckon that's the first time I've taken it off in 3 years. It wasn't actually that bad behind it. All cleaned now and back in place. Thanks everyone. Coffee is tasting better and better now too. Also added the IMS (?) screen suggested above. A work of art.


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## mark_gaggica_classic (Jun 6, 2016)

Missy said:


> And replace the rubber gasket, which I'm presuming you've taken out.


Not as yet, need to order one. Though it still seems to be functioning 100%. No escape of pressure from the PF.


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