Boiler overfilling during extraction, leaking from relief valve

Equipment doesn't work? Troubleshooting? If you're handy, members can help.

#1: Post by Flitzgordon »

Has a Mitica and I've been having leakage issues.

With the heating element unplugged, i pull the lever and water is coming out of the vacuum relief valve located on top.

I did a visual check on the refill solenoid's internal and it seems alright. The solenoid could magnetize during refill.
Water probe looks clean.

I removed the excess water from the boiler and things seem to work, no more of overfilling for the time being, but I believe it may return if i can't identify the issue.

What could the problem be?


#2: Post by JRising »

If it went away, at least temporarily, it was likely leakage through the boiler-fill solenoid. When you looked at it, you released whatever was holding it open.

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Flitzgordon (original poster)

#3: Post by Flitzgordon (original poster) »

That's what i suspect, i replaced a new solenoid 2 months ago so it's still new. That's why I'm not sure if that's really the cause.
When i took apart the valve, the gasket looks fine, i did saw a little speck of limescale.
I used a screwdriver to feel the solenoid's magnetism and it was there.

As far as I can tell, the route to the boiler goes from the pump -> refill solenoid -> boiler.
Unless the heat exchanger is leaking for some reason. Right now, the brew pressure seems fine and no signs of extreme heat.
When I pulled up the lever, the leak from the vacuum relief was almost instant. Is this the biggest hint?

I doubt the OPV plays a part either, since that governs the flow to the heat exchanger than the boiler.

There's only one minimum level probe. That might another possible link?
I've checked the regulator and there are no water or burn marks.

Anyone has more to add or comment will be deeply appreciated.

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#4: Post by emradguy »

Have you pulled and inspected the fill probe? If it needs cleaning and polishing, it could lead to a boiler overfill problem, and that could cause pump or line pressure to drive enough water into it to trip the safety relief valve.

Flitzgordon (original poster)

#5: Post by Flitzgordon (original poster) »

The water probe looks clean.
I've tried draining the boiler a couple of times, they worked as expected.

Problem is I can't replicate the problem right now, just worried that it might return.