Gaggia Classic leaking during heat up

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
Lakritskatten
Posts: 6
Joined: 5 years ago

#1: Post by Lakritskatten »

Hi,

My gaggia classic (2017) started leaking during heat up after a descaling session.
As soon as the machine reaches the right temperature it stops, but until then its pouring and steaming from the group head.
The small rubber ball seal looks good and there is no visible traces of scale.

Any ideas?

edit: i actually think that it might be leaking until the water in the boiler is all out

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C-Antonio
Posts: 376
Joined: 5 years ago

#2: Post by C-Antonio »

So its one of those with the group valve it seems.
I would presume that everything was dry behind the screen before this happens (basically that you didnt do a flush and what you see is not the water remaining behind that evaporates with the heat)
Its the group valve that keeps all closed against the pressure developed while heating up, things are that either there is something where the little ball stopper seats that doesnt lets it do its job or its the spring that is a bit compressed.
Try taking apart the valve group (you can find videos online if you need a visual but from your post I think you already took it apart, however in a video they might show how things look when they are worn), and stretch a bit the spring. Make sure the bottom part is screwed all the way (if you unscrew it a bit you would relax the spring). Dont stretch it too much, if its not enough eventually you can always repeat it.
Make sure that the mushroom is nice and round and not shaped like a pear, which would mean you need to change it. and if you can try to give a look at the valve seat (a cellphone helps for that)
“Eh sì sì sì…sembra facile (fare un buon caffè)!”

Lakritskatten (original poster)
Posts: 6
Joined: 5 years ago

#3: Post by Lakritskatten (original poster) »

C-Antonio wrote:So its one of those with the group valve it seems.
Make sure that the mushroom is nice and round and not shaped like a pear, which would mean you need to change it. and if you can try to give a look at the valve seat (a cellphone helps for that)
Thank you for such a thorough reply!
As far as I can tell the rubber mushroom looks to be in mint condition, and so does the part that should form a seal with it. I tried to stretch the spring a bit without seeing any difference.

Although the machine was dripping a bit before my descale it is nothing compared to what it does now. I would say that it lets out a 200ml (a cup-ish) of water in about 30seconds. So something must have happened during the descale, maybe the rubber seal stiffened up from the detergent?

Anyway, I'm guessing I'll try to get a hold of a new gasket and spring. Because it couldn't really be anything else, could it?
Also, just to make sure - it's only the mushroom and a spring that is supposed to go inside the holder which the mushroom facing upwards?

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C-Antonio
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#4: Post by C-Antonio replying to Lakritskatten »

thats a lot of water, not good for the heating element...
I dont think the detergent stiffened the mushroom, unless you used something not made to clean a coffee machine (like vinegar or CLR etc, that stuff ruins the plastic parts and seals). I would find whats wrong before buying parts.

The valve all together its a single unit that can be disassembled:


often when you go taking it apart the main body of the barrel ends staying in the grouphead and you just end taking off the bottom half with the spring and the mushroom. The reason the body of the valve remains stuck in there could be scale or dirt etc.
Make sure that what is not screwed in properly is the valve body and the leak comes from there rather than the valve itself.
To take off the whole barrel you can use a very wide screwdriver or a simple flat piece of metal that fits the barrel slot. Be careful, you dont want to ruin that bit of a slot the barrel has or it will be hard to work on the machine if you ever need to replace the whole valve assembly, get something that fits snugly (there is a tool made on purpose but its nothing more than a flat bar)
As you can see from the pictures the whole valve assembly seals into the bottom of the boiler with an O-ring (that red one).

I found a video showing you the cleaning, should clear some doubts, its not on a classic but the part is the same and works the same way. I see in the thumbnail they use a coin, try to use something flat with corners, the round coin sometimes doesnt grab enough of the slot and risks to ruin it.
“Eh sì sì sì…sembra facile (fare un buon caffè)!”

Lakritskatten (original poster)
Posts: 6
Joined: 5 years ago

#5: Post by Lakritskatten (original poster) »

C-Antonio wrote: I dont think the detergent stiffened the mushroom...
Thanks again!
I got hold of a new gasket with no luck at all.
I talked to a repairman and he thought that the pipe inside the boiler which makes sure it feeds water from the top of the tank is cracked. Sending it back hoping that the warranty will cover it!

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C-Antonio
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#6: Post by C-Antonio »

It would have to be broken at the hub, where the valve assembly screws in, to be able to leak, any higher and a working valve would still hold the water, you would be brewing with colder water...
If that is broken they would replace the whole bottom half of the boiler, which is also the grouphead etc. its a 35-50 euros part plus the new gasket and brew valve and labour... if they send it back to you without anything to pay and no work done then its still something you can do by yourself (and you would reuse whats good from the old).
Its a strange place to crack but they cant also hardly fault you for something like that, you would be catching the warranty right at the end of its period.

Put back on all the old parts and keep whatever new part you bought as spare for future repairs, dont send them the machine with the new stuff in.
“Eh sì sì sì…sembra facile (fare un buon caffè)!”

Lakritskatten (original poster)
Posts: 6
Joined: 5 years ago

#7: Post by Lakritskatten (original poster) »

C-Antonio wrote: Its a strange place to crack but they cant also hardly fault you for something like that, you would be catching the warranty right at the end of its period.
Thanks! Fingers crossed!