# Portafilter Flying Off



## CoffeeloverChris (Sep 4, 2020)

Hi

I hope you can help. I have a beloved Gaggia Classic, that I've looked after over the years, taken apart, rebuilt, changed parts etc! Recently, when brewing - the portafilter handle started turning, until wooosh! it pops ou! I recently replaced the portafilter because I thought the lugs might be worn. I also replaced the gasket head seal. It's still happening. I've adjusted the grind and all the usual things - but can't solve the problem. I really have to yank the handle into place with some force or even hold it in place to stop it from happening. Could it be something to do with pressure? I was wondering if it was worth investing in a pressure gauge to check and adjust. Any thoughts would be appreciated, perhaps you've managed to solve the problem in the past?

Thank you!

Chris


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## MediumRoastSteam (Jul 7, 2015)

The technical term For this is a portafilter sneeze. 😉 - it should not happen. It's unlikely to be related to pressure.

does he porta filter lock at the 6 o'clock position? Is this how far it will go? Have you replaced with the correct gasket thickness, and put the right way up?

is the OPV (expansion valve, aka Over Pressure Valve working)? When you backflush, is there water coming out of the other hose? When you finish the shot, does water come out of the pipe into the drip tray?

Can you do a video of that happening?


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## El carajillo (Mar 16, 2013)

As above, first check, does it comfortably lock in to 6 o'clock position ? Is the seal the correct thickness 8 mm usually.

Were the lugs worn ? Are the lugs on the new P/F the same shape , thickness and taper ?

Were there any bits of old group seal left in place ? Groove completely clean ?


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## CoffeeloverChris (Sep 4, 2020)

Hi - thanks for your help so far.

The lugs on the new PF are the same, but not worn - and it does lock in 6 0'clock position. Just after the brew has started, 50% of the time, the handle starts moving clockwise and then goes.



I haven't tried backflushing. Is there a simple technique?


I'm pretty sure there's water coming out of the pipe into the drip tray at the end of the shot.


I'll check the thickness of the seal - I definitely fitted it the right way up and made sure the groove was clean. I'm at work at the moment, but will try and upload a video tomorrow


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## MediumRoastSteam (Jul 7, 2015)

CoffeeloverChris said:


> Hi - thanks for your help so far.
> 
> The lugs on the new PF are the same, but not worn - and it does lock in 6 0'clock position. Just after the brew has started, 50% of the time, the handle starts moving clockwise and then goes.
> 
> ...


 Gaggia Classic gaskets are 8.5mm thick. Flat side faces down. Let's not worry about backflushing at the moment. When you pull a shot, there are two hoses going into the drip tray: one is the pump inlet the other is the return of the OPV. Make sure there's water returning. How far can you lock the PF in? With reasonable force, does it stop at 6 o'clock? You haven't put any grease on the gasket have you? And I take there's no coffee gunk build up on it? And no leaks? Report back.


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## El carajillo (Mar 16, 2013)

With the amount of pressure building up, if there is no water coming from the OPV return pipe it is likely the OPV is stuck / seized as it's purpose is to release excess pressure above that what it is set to (usually adjusted to 9 bar by owner OR 15 bar if as factory set).

Also check there is a good splash from the release pipe when releasing pressure/ ending brew. Strip / check / clean the solenoid valve. Is the solenoid clicking ?


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## CoffeeloverChris (Sep 4, 2020)

Morning!

I've run a few tests this morning.



There's no grease on the seal - it's pretty new


Pipe running into drip tray is releasing water at the end of the shot


I placed the plastic pipes into separate containers, one with water (to feed the pump) one without. No water emerged from the return pipe at any point?


I've noticed that my PF isn't quite getting to 6 O'Clock - it's about 7 O'Clock. I checked the seal last night - and although it's tightly in place, it does stand about a mm proud. I've ordered a thinner one.


I'll try and upload a video. I made three shots this morning. on the third - it blew. I've also taken a photo from above of the PF position.


/monthly_2020_09/Gaggia-1.mp4.4e502b4a7df949acf0225a6d00438a01.mp4" type="video/mp4">
View attachment Gaggia-1.mp4


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## El carajillo (Mar 16, 2013)

I think you need to check / possibly remove the OPV , strip it down and make sure the seal/ valve is moving freely. 17 mm spanner or adjustable to remove nut.

Measure from top down to slotted / hex holed adjuster (accurately) this will allow you to reset it to the same position / pressure when you reassemble.

Check for damage on the seal, components must move freely.


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## MediumRoastSteam (Jul 7, 2015)

Ok. The OPV is not opening because all the pressure is going through the Coffee puck. You are grinding far too coarse!

But this is good. So it's not pressure related I don't think. All I can think of is they you did not mount the dispersion place or seated the gasket correctly.

Sent from my iPhone using Tapatalk


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## CoffeeloverChris (Sep 4, 2020)

Surely the finer the grind - the higher the pressure? Doesn't a coarse grind mean less pressure?


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## CoffeeloverChris (Sep 4, 2020)

Hi

An update. I stripped and cleaned the OPV assembly. There is now some water coming back through the pipe: It's only a small amount - is that OK? I haven't pulled many shots yet - but will try again in the morning.

C


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## MediumRoastSteam (Jul 7, 2015)

CoffeeloverChris said:


> Hi
> 
> An update. I stripped and cleaned the OPV assembly. There is now some water coming back through the pipe: It's only a small amount - is that OK? I haven't pulled many shots yet - but will try again in the morning.
> 
> C


 It depends of how much pressure it's going through the puck. The more pressure against the puck, the more water it will come out from the hose. Take a video of your shot making. You should weight your input/output. So, 18g in, 36g out in approx 30 seconds.

if you are not, fill in your basket and aim for 50/60ml of coffee in approx. 30 seconds.

in your video, it seems your grind is far too coarse. Puck is then very porous, and there's no real pressure going via the expansion valve. I would not expect much or any water coming out from the OPV. I would not drink that coffee either! 😂

edit: I just re-watched your video. There's a lot of water coming out on the side when you finish the shot, to the right. I'll say again: are you sure the gasket is seated correctly, and likewise the dispersion plate and shower sceeen?


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## El carajillo (Mar 16, 2013)

CoffeeloverChris said:


> Hi
> 
> An update. I stripped and cleaned the OPV assembly. There is now some water coming back through the pipe: It's only a small amount - is that OK? I haven't pulled many shots yet - but will try again in the morning.
> 
> C


 YES. The flow will vary depending on [ pressure from pump] [pressure set on OPV] and [ resistance to flow through puck]. [ fineness of grind and age / storage of beans]


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## CoffeeloverChris (Sep 4, 2020)

MediumRoastSteam said:


> It depends of how much pressure it's going through the puck. The more pressure against the puck, the more water it will come out from the hose. Take a video of your shot making. You should weight your input/output. So, 18g in, 36g out in approx 30 seconds.
> 
> if you are not, fill in your basket and aim for 50/60ml of coffee in approx. 30 seconds.
> 
> ...


 Hi - the large amount water in the video was a demonstration of what happens when the handle turns under pressure and blows. The gasket is seated correctly (although I've ordered an 8.5mm one to see if that makes a difference). Yes, th dispersion plate and shower screen all good. I removed/cleaned/replaced group head etc etc over the weekend too.


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## MediumRoastSteam (Jul 7, 2015)

Blimey - if you are locking the PF not even at 6 o'clock with an 8mm gasket... Something is not right with the assembly of the lower group. The Gaggia Classic gaskets are 8.5mm thick.

This should mean your portafilter will lock even earlier, outside of the "safe" zone.


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## Inspector (Feb 23, 2017)

Every time I had similar issue it was related blocked solenoid. Happened like 3 times or so in my 3.5 years ownership of gaggia classic. Take your time with backflushing. With cafiza then without cafiza. Repeat if necessary until you get a nice and clean whoosh from steel pipe. If it is blocked you will feel it when machine is hot, it's hard to lock the portafilter even and it moves under pressure.


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## CoffeeloverChris (Sep 4, 2020)

MediumRoastSteam said:


> Blimey - if you are locking the PF not even at 6 o'clock with an 8mm gasket... Something is not right with the assembly of the lower group. The Gaggia Classic gaskets are 8.5mm thick.
> 
> This should mean your portafilter will lock even earlier, outside of the "safe" zone.


 I've just fitted an 8.5 - and it's making a difference. It's now locking at between 5 O'Clock and 6'Clock. Having stripped down the The one I had in was too thick (even though I ordered it from an official Gaggia supplier. Having stripped and cleaned the OPV too, I think the problem's solved! I'll give you an update. Thanks for advice so far.


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## MediumRoastSteam (Jul 7, 2015)

CoffeeloverChris said:


> Hi - the large amount water in the video was a demonstration of what happens when the handle turns under pressure and blows. The gasket is seated correctly (although I've ordered an 8.5mm one to see if that makes a difference). Yes, th dispersion plate and shower screen all good. I removed/cleaned/replaced group head etc etc over the weekend too.


 Well yes. If it was too thick... You can't lock the PF in. And it will sneeze!


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## Agentb (Feb 11, 2017)

There's a couple of similar threads, i had a similar experience (different cause i think) which led to the the realization that there's more to a Gaggia group gasket than just rubber, black and circular 😹

https://coffeeforums.co.uk/topic/44977-group-head-gasket-seems-stiff-on-gaggia-classic/

and

https://coffeeforums.co.uk/topic/47080-gaggia-classic-kicking-out-group-head/



CoffeeloverChris said:


> I was wondering if it was worth investing in a pressure gauge to check and adjust.


 In the "Pay it Forward" forum there is a thread, put your name on that and one will arrive.

https://coffeeforums.co.uk/topic/22663-one-more-classic-pressure-gauge-available/

good luck. 👍


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## CoffeeloverChris (Sep 4, 2020)

Agentb said:


> There's a couple of similar threads, i had a similar experience (different cause i think) which led to the the realization that there's more to a Gaggia group gasket than just rubber, black and circular 😹
> 
> https://coffeeforums.co.uk/topic/44977-group-head-gasket-seems-stiff-on-gaggia-classic/
> 
> ...


 Thank you! Very helpful


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## CoffeeloverChris (Sep 4, 2020)

Inspector said:


> Every time I had similar issue it was related blocked solenoid. Happened like 3 times or so in my 3.5 years ownership of gaggia classic. Take your time with backflushing. With cafiza then without cafiza. Repeat if necessary until you get a nice and clean whoosh from steel pipe. If it is blocked you will feel it when machine is hot, it's hard to lock the portafilter even and it moves under pressure.


 Hi

After your post - I invested in some Cafiza and blind basket. I've never done backfushing before - I'm sure it'll be good for the machine. I did get some movement from the PF when under pressure and had to hold it in place at one point. I was getting a good 'whoosh' from the steel pipe though. I thought I'd fixed the problem after fitting a thinner Group gasket - but just pulled a shot and the PF moving again (although it seems to rest rather then keep turning too far). I wonder if when stripping down the OPV and reassembling I altered the pressure. I've a gauge arriving this week - so I'll be able to check and report back!


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## Inspector (Feb 23, 2017)

what group gasket you are using at the moment.

i have hardly benefited from blue cafelat with my naked portafilter (was fine with original portafilter). it always leaked from back of portafilter after few weeks of use and i came back to regular cheapo black gasket which has been faultless.


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## MediumRoastSteam (Jul 7, 2015)

Inspector said:


> i have hardly benefited from blue cafelat with my naked portafilter (was fine with original portafilter). it always leaked from back of portafilter after few weeks of use and i came back to regular cheapo black gasket which has been faultless.


 Did you ever managed to figure out why? I mean, it's only silicone instead of rubber. It shouldn't be an issue regarding the seal it forms. Where you locking the PF at 6 o'clock?


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## Inspector (Feb 23, 2017)

Cafelat is slightly lower than the regular rubber gasket and I think lugs on my bottomless portafilter is slimmer than original portafilter. That's why I can lock bottomless to 5 o'clock and original to 6 o'clock with cafelat.


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## CoffeeloverChris (Sep 4, 2020)

I just wanted to say thanks to all of you for contributing to this thread. It's been amazing.

I'm now pulling the perfect espresso. I think it's been a combination of things:



A thinner gasket made a huge difference.


Servicing and cleaning the OPV


Starting a regime of back-flushing


Then I invested in a cheap cheap pressure guage. My pressure was running far too high. I've now adjusted to 10 bar. I'm getting a lovely crema, great tasting espresso and no movement of the portafilter. Happy all round!


Thanks again.

C


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