Pressure bouncing on Breville Infuser

Need help with equipment usage or want to share your latest discovery?

#1: Post by mook613 »

I recently purchased a used Breville 840. When trying to pull a shot the pressure will go up to the middle of the gauge (between the two screws) where I am told is the ideal pressure. There are no numbers on the gauge, so don't ask what the pressure is actually at.
Anyways.... once the pressure goes up to that point it rapidly will drop quite a bit and then build up again. This will happen a few times until the pressure holds for the remainder of the shots. This video shows what I am talking about:
I have disassembled the Ulka EFP5 pump, which was super clean, but I soaked the parts in vinegar anyways, then tightened it all back up. Still has the same issue.
While the problem was happening I watched the tube connected to the over-pressure valve and no water was coming through it.
Would ordering a new pump work? The only pump I can get is the EX5, which has a different fitting on top, so I would be using the same over-pressure valve as I am now. Would this be a problem?

Any help would be much appreciated.


#2: Post by LukeFlynn »

Could be a faulty OPV.. I can't believe they don't have numbers on the pressure gauge.. how absurd.. what is the point? Are you using the unpressurised baskets? How is the taste?

Both fittings are the same I think, one is plastic and one is brass.. I replaced my old oscar pump with that one and I just had to swap out a tiny fitting.

Wait.. PUMP PULSING! I had this problem on my Oscar.. It's horrendous and always causes awful channeling. I fixed it by replacing the pump (mine was also clean).. it could also be the OPV.. but I would assume the pump since it's making that awful noise.

mook613 (original poster)

#3: Post by mook613 (original poster) »

Using unpressurized basket, and if I back my grinder out by a bit then I can keep the pressure under the point where it causes the bouncing. But that results in a slightly underextracted shot. Using 16g at a 24-25 second extraction and pulling just about 35g of coffee out.
The taste is just a touch on the bright side, which is expected here. But i'd like to grind a bit finer and bring out a bit more of the body that I know I could extract.

I'll have a new pump ordered and hope for the best. Can't seem to find the part for just the OPV, so I will need to re-use the one on it now.

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#4: Post by mzedith »

I'm not an expert by any means. Before my recent upgrade I was using an infuser. I noticed it would bounce sometimes. If the water temp wasn't ready or I had uneven distribution in my portafilter.

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#5: Post by mzedith »

My infuser worked well with a 14 gram shot, un pressurized basket and a 25 seconds. Above 14 grams the puck would get stuck on the screen and it would definitely bounce.

mook613 (original poster)

#6: Post by mook613 (original poster) »

So this morning I tried to pull a shot with the reduced coffee amount. First off, so long as I follow the guideline of trying to level the edge of the tamper with the edge of the portafilter I don't see why the space between the screen and the ground beans would be a problem.

That being said, I don't think the height of the grinds was the problem. Tried using the machine this morning and pressure built slowly, then dropped and kept on going lower. Tried some more shots and was just wasting beans because the pressure could not build up high enough. My guess is that the pump was on its way out which was causing the pressure bouncing, and then sometime this morning died and now isn't able to produce steady pressure anymore.

I have ordered a new pump and am impatiently waiting for its delivery.

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#7: Post by mzedith »

try one last thing. Don't put a lot of pressure on your tamp. just level it off and smooth the surface with your tamper.


#8: Post by LukeFlynn replying to mzedith »

FWIW, this temporarily fixed the similar issue I was having... I prefer tamping around 30 lbs though just because old habits die hard.

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#9: Post by mzedith replying to LukeFlynn »

I agree. I just never had any luck doing a 30 lb tamp on my infuser.


#10: Post by LukeFlynn replying to mzedith »

Never had an Infuser, but I had a seemingly identical problem with my Oscar.. Brevilles machines do look extremely classy..