Need help identifying valve in Bezzera BZ02S

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ryguy
Posts: 16
Joined: 13 years ago

#1: Post by ryguy »

I posted this on coffeegeek about a week ago and never got a response...here's hoping the HB community has some ideas!

In the picture below, I can't figure out what valve #2 is. Both 1 and 2 have hoses running back to the tank. Valve #1 I believe is the OPV because it only flows when the pump is under pressure (during a shot or backflush). Valve #2 doesn't flow at all under pressure, but it sort of sputters when there's no pressure. Any idea what it is and what its purpose is? The reason I ask is it seems to be making a lot of noise; if I plug up valve #2's line while running the pump, a lot of buzzing/rattling goes away.

FYI, it's a little hard to tell from that angle, but neither of the valves is connected to the Sirai solenoid; that's the boiler fill solenoid and is earlier in the water path.

Ryan

CSME9
Posts: 499
Joined: 19 years ago

#2: Post by CSME9 »

The second one appears to be the vacuum breaker valve discharge tube, the valve normally sputters a little as the boiler gets to temperature and then the valve closes. These valves seals tend to go bad after a while and will sputter and hiss steam/water while the boiler is up to temp. Without the silicone tube they would sputter water inside the machines electronics, routing the tube to the drip tray or water tank will keep the inside of your machine dry.The valve is easy to replace for about $10.

WS

ryguy (original poster)
Posts: 16
Joined: 13 years ago

#3: Post by ryguy (original poster) »

Thanks for the reply, Will. This machine does have a vacuum breaker but it is on top of the boiler with the probes and safety pressure valve. The 2 valves in question are definitely on the "cold" side of the water circuit - after the pump and before the HX. Here's a wider image that may help give a little context:
Ryan

CSME9
Posts: 499
Joined: 19 years ago

#4: Post by CSME9 »

I am not certain but perhaps it is part of the pumps deaerator and is tied into the opv so they both drain back to the water tank.

WS