La Pavoni Pressure Release Won't Close

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#1: Post by me »

On my millennium LP, sometimes the safety valve will not close, and will keep emitting steam for several minutes, preventing the machine from reaching pressure. Turning the machine off and on will fix it, but is this normal behavior? Or is it time for a replacement or cleaning?

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#2: Post by homeburrero »

Newer machines have a small anti-vac valve combined with the safety valve. The safety valve seat is held down by a spring, and the inner anti-vac valve dangles freely and is closed by steam pressure from below. Both valves are in #19 in the pic below:

It's supposed to hiss a little when the machine first builds some steam pressure, then close as the pressure builds. Just like the little button on a pressure cooker. Sometimes the inner anti-vac gets a little sticky and a gentle rap on the valve cap with a wooden spoon will cause it to close and quit hissing.

If residue in there is making them too sticky then you can usually fix that by disassembling and cleaning the valve and seats. If you do that it's wise to use a thin 16mm wrench to make sure that you don't unscrew the lower fitting nut while unscrewing the upper cap nut (#18 in the pic) . That washer and nut #45 and #46 is inside the boiler and you want those to stay snug with the lower fitting when removing the top nut.

P.S. A 16mm bicycle cone wrench is a perfect fit for holding that lower fitting.
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