# Hissing from Cherub after use?



## pangol1n

Hi guys,

So recently my Cherub has started hissing after use, I can hear a faint hiss after I've pulled a shot/steamed some milk and switched it off. I don't remember this happening before, but maybe I was just not paying attention - is it normal? I'm obviously kind of worried because it was purchased second hand so I've got no warranty on it.


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## 4515

Not sure if its the same as the L1 but I had a hissing initially. It was the pressure release valve on top of the boiler that wasnt fully seated. A sharp tap on the plunger on the valve got it sealed and its never happened since


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## froggystyle

From inside or via the steam wand?


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## pangol1n

The hissing seems to be coming from inside - the pressure on the gauge after being left to heat up seems to stabilise at 0.9bar, just within the green section, and then slowly drop every two minutes before reheating up again.


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## 4515

Take the lid off and check the PRV - that would be my first suspect. With the lid off you should be able to see where the noise if coming from


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## pangol1n

Will do that and report back - cheers!


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## froggystyle

Why is it sitting at 9 bar if your the pump is not running?

I though these machines only built pressure when the pump is running.


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## espressotechno

Hissing is usually due to a leaky anti-vac valve, or safety valve, or compression joint somewhere.

Pull the mains plug; take the lid off and listen / look around: You might just see the steam escaping, or sense it with a carefully waved hand.....

Tap the suspect valve to reseat it; if still leaking fit a new valve (especially the safety valve).

Tweek a leaky compression joint with a spanner - if it still leaks, remove & clean the connection, then refit with teflon tape.


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## pangol1n

Thanks guys, will have a look and report back - I'm away for work tomorrow but I should have some time on Thursday to sort it out properly and diagnose the problem.


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## pangol1n

So I had a quick look at the machine, the hissing seems to be coming from a silver valve on the boiler, to the left of the pressure release valve. I've taken a video of the disassembly where I point out the hissing culprit:











I've also taken some pictures but only photo 2 seems to show the valve in question (the silver valve to the left of the OPV)









I've also included a Google Drive link to the folder with everything in one place:

https://drive.google.com/open?id=0B0TqnQ1XLIRLYmlDQUZfS3Znd1U&authuser=0


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## El carajillo

It is the anti vac valve, unscrew it from the boiler and dismantle, carefully flick out the small circlip on the end of the pin and ( use a small screwdriver) check /clean the parts/ possibly with de-scaler. Reassemble and refit


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## pangol1n

Thanks very much for the info - is it a relatively easy task to perform? A full service on the machine is £240 so obviously I don't want to spend that much, but I'd be worried about breaking the machine (not to say that I don't want to attempt it, I definitely do) - would the anti-vac valve be responsible for the (relatively) rapidly dropping pressure then?


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## El carajillo

Yes it is a simple task, clean around the valve to remove any scale/ muck. Use a spanner to unscrew it from the boiler, lift it off/out (it is only short 20 mm ?) Hold the nut part insert a small flat screwdriver into one of the recesses on the circlip and twist, circlip will fly off. Press out centre pin and examine the seal on the underside. Clean up these components and re assemble, press circlip back into groove and screw back into boiler.(Check for seal between boiler and valve OR it is probably PTFE tape= plumbers tape /50 p a roll)

YES this could be the cause of pressure drop as steam is leaking past the valve (it works both ways)


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## pangol1n

Okay that's great, thanks very much! I'll give that a go when I'm back home in a week and a half, will report here on how it goes!

Cheers!


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## pangol1n

Hi guys, so I've gone to try and remove the anti-vac valve from the boiler, but it seems stuck on, and putting too much pressure on the anti vac valve is moving the other components - do you guys have any tips for how to get the valve off? Cheers


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## espressotechno

Use a socket set with an extension bar & try to undo the a/v valve with a quick jerk, rather than slowly. A wee squirt of WD 40 can help.

Don't worry if the valve is damaged - new ones are quite cheap !


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## pangol1n

Cheers, will give that a go now - I've actually bought a new one from Fracino because I figured with boiler valves it would be good practice to just replace it, and it should be easy enough to install once I can get this damned old one off!


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## pangol1n

So through extending the socket I could probably get enough force if I really pushed, but the rest of the boiler components seem to be moving at the same time, including the ones that join the group/steam wand, and I'm worried about forcing it too much is going to dislodge a compression joint or something - are these machines fragile / am I at a risk of breaking something just by trying to twist off the AV valve, or should I really just go for it? Going to go buy some WD-40 to try and loosen it up and see what happens.


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## pangol1n

So with a new socket set and a friend's help I finally got the old valve off and got the new one in - happy to report that the hissing has stopped completely, even if the pressure is still a bit low on the machine. Is there a way to adjust the pressure of the machine? Perhaps through fiddling with that dial on the OPV valve?

Cheers for the help anyway guys, you've saved me a couple of hundred quid here!


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## pangol1n

Also I'm not sure if this is noteworthy at all, but whenever I'm pulling a shot, water is flowing back into the tank from the small rubber tube that joins the top of the tank itself - is this normal?


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## gwapenut

pangol1n said:


> Also I'm not sure if this is noteworthy at all, but whenever I'm pulling a shot, water is flowing back into the tank from the small rubber tube that joins the top of the tank itself - is this normal?


Water flowing back in is perfectly normal I think - it's when the pressure exceeds the maximum set, a valve opens and pressure is relieved by this flow of water back into the tank.

The valves do seem to be the weakest link on the cherubs - I still have occasional hissing on mine after use, and I've had to replace 2 or 3 safety pressure valves. Think my particular cherub was a bit of a dog to be honest, but apart from the occasional hissing I've got it working and fixed within the warranty period. Happy to report that Fracino and in particular Louise who works there have been great, and am now finally happy with my cherub.

What does reassure me from my unfortunate machine is that should anything go wrong out of warranty, there'll be good support from Fracino and affordable parts, plus support from this forum, to get it sorted at minimal expense.


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