Turned off my Andreja 3.5 months ago, and then tried to fire it up this morning. It was running fine back in March. Filled it with water, flipped the switch, pump ran briefly and it began heating up. First the vent valve on top of the border did not close as it usually does. No big deal, I wiggled the little thingy in the top and it closed. Heating continued for a few minutes, then there was a medium-loud "POP".

It was enough to startle me, and I turned it off. Pulled a few screws and peeked inside. Started it up again, same result, two POPs.

It is now sitting on the workbench, partially disassembled, and I am contemplating my next move. I've had this machine 16 years and have done all the repairs on it, but this is a new one for me. Has anyone else encountered this? Any ideas? Thanks!

Doing a little messing around here, took off the back and the side panels. Turned it on and observed. The vent valve spews a fair amount of water, some of which hits the pressurestat. There were no pops this time. I think the pops this morning could have been one of the following:

1) The water spewing from the vent valve could have hit some electrical components, causing a pop.
2) It could have been the safety valve letting off steam.

I'm leaning toward the latter, as if the electric components were the problem, I would have expected to trip a breaker or the machine to shut down. Neither of those happened.

I'm going to move it back to the kitchen, sans sides and back so I can observe, and give espresso another "shot" in the morning.

If the water from the vent valve is causing the problem, I'm thinking of putting a foil cap over the vent valve to contain the spewing. Good idea? No?

If enough water is coming out of a vacuum breaker that it actually concerns you, maybe the boiler is overfilled or overfilling. After letting water out, does the auto-fill seem to work? If you take the boiler-fill probe out, how close to the top of the boiler is the surface? Can you clean the probe and make it better?

Hi JRising, and thanks for the ideas. I will put that on the list to check/clean, that's a good idea.

This morning I brought the machine, sans sides and with back unscrewed, into the kitchen to make an espresso. My wife was thrilled with the look of the bare internals of a 16-year-old machine, as you might imagine. I fashioned a little foil fence and put it around the vent valve, which stopped most of the water from spewing on anything else.

Machine started and ran as normal, although it did take about 45-60 minutes to fully heat up (normal is 30 minutes). I ran water thru the grouphead and steam thru the wand, which helped. Pulled a shot and it worked fine. I left it on, as I need to pull a few shots to get my grinder calibrated to this coffee (had to buy some, didn't have my roaster), and I'll pull another soon.

I'm wondering if this is kinda like asking an old man to run the 100 meter dash, and expecting him to come out of the blocks like Usain Bolt, but without any training. He will creak, groan, pop joints, maybe pull a muscle.

OK, I've left this thing on all day and observed it. Pulled another 3 shots getting the grind dialed in (yes I'm vibrating) and the ol' Andreja played nice. To be clear, the "vent valve" I'm referring to is Item #70 on the diagram, referred to as "Valvola Sfiato". Which translates to "Breather Valve" using google translate.

I'll do a complete cleanup and de-scale in the coming days, including the boiler fill probe. And I'll keep the foil fence in place to prevent splashing, at least until that is done. Might have to replace that breather valve, but I'll wait to see if the de-scale helps.

FYI, the pop-up boiler valve on my machine came with a small metal (I think it was aluminum) cup that kept the dribbles of water from dripping all over the place when it was heating up. The idea was that this small amount of water would boil off while the machine was in use. Well, after a few years it just corroded away. I removed the valve, cleaned the boiler top, and replaced the valve without the cup. I thought the cup was a good idea but poorly engineered...probably corroded due to galvanic action), but I couldn't find a replacement. Maybe you can. If the valve is working properly (i.e. closes quickly enough when boiler steam pressure builds), the small amount of water that drips on the boiler should evaporate quickly. But it could create problems.

That's why I like machines that divert this water away from the innards to the drip pan.

Hi Pressino, my machine also has a small cup around the breather valve. But it is shorter than the valve, so it does not catch water that spews out with some force. The water that stays within the cup area does evaporate pretty quick. But when it hits the pressurestat, it's there for a while. Still planning on a de-scale here soon, and I'll pay special attention to the breather valve.

One of the mods I did for my old AP was to replace that valve to one with a nipple that allow a silicone tube to be attached, which I ran down to the drip tray. No more mess and worry about water spraying the electrical components on top of the boiler. What a stupid design smh.

Excellent idea! And yes, it was a poor design by Quickmill.

Here is the best pic I could find in my photos. Hope this helps others.