Hi All,

I'm a long time "lurker" but now a first time poster. I did a decent amount of searching for my issue and didn't seem to find much, so I'm hoping y'all can help me out.

I recently picked up a used Millenium II for a steal ($350) as an upgrade to my trusty Silvia. My best guess is it's about 8-10yrs old with light use (in storage the last 4yrs, 1-2 drinks/day prior) and was serviced prior to storage. I did limited testing prior to purchase, but everything seemed to work as it should (minus user error). What I quickly noticed is I don't have steam pressure without a little bit of trickery to the machine.

In order to get good (i.e. "normal") steam pressure, I had to invent a process of:
1 - bleed the little steam in the boiler (very quick drop from 1.3 bar to .5)
2 - open the hot water valve until the boiler auto-fill comes on
3 - good to go

Also, the more I use the machine the better the steam pressure seems to be. My initial thoughts are that the pressurestat could use replacing (I hope it's this easy), or I have a leak somewhere. I opened the case tonight to check for any leaks. I couldn't hear or see anything (used a chromed spoon around all the fittings to check for condensation/steam) that would indicate a leak. However, there does seem to be some corrosion around some of the fittings. I'm hoping this is normal based on age of the machine though.

So - the ask I have of y'all is your opinion/thoughts. Pressurestat? Or do I need to examine these fittings/welds closer? Thanks!!

Remove steam tip & clean, and check the steam thru the wand, wand may be clogged near the valve. Fittings look pretty good except slight scaling near heat elem connections. Remove the vacuum breaker valve and descale it (or replace it) when bad they create false boiler pressure, and once you open the steam wand and release the pressure the boiler reaches full pressure quickly.

Thanks CSME9! The vacuum breaker makes sense as it comes up to normal pressure and stays there after a few bleed offs. I'll give descaling it a shot.

dont worry about the fittings... thats normal.
? the steam tip is obviously clear.
If there was a blockage in the wand or tip it would not let the boiler pressure gauge drop like that.
You didnt show or mention if the heater "ON" light comes on when that boiler pressure drops. ?
does it come on and stay on until the pressure gauge is back up to 1+bar ?
To me, it looks like you have a partial blockage in the steam port back at the boiler ..possibly scale.
You may have to descale the whole system to be sure.
Or, ..if you are confident, strip off the steam line back at the boiler and check for any blockages.

Thanks for the input Beenbag. To answer your question: yes, the heat element comes on after the drop and stays on until it's back up to pressure.

Again, this only happens at first go with the steam. After I bleed off or use the hot water tap I have great steam pressure. I'm not very well versed in the boiler mechanics - how would a partial block impact this? If it's partially blocked wouldn't the issue be constant and not resolve itself after the pressure flush? Or are you thinking along the lines of CSME9 that something is causing false pressure at start up?

italoio78 wrote: yes, the heat element comes on after the drop and stays on until it's back up to pressure.

Again, this only happens at first go with the steam. After I bleed off or use the hot water tap I have great steam pressure. ?

Ahh ! OK, that wasnt clear from your first post, but if its only on "Start up" from cold then its a classic "false Pressure" situation as CSME9 said, caused by air trapped in the boiler after a cool down.
The most likely cause ir the vac relief valve on the top of the boiler, whose job it is to expel any trapped air as the boiler warms up. You need to replace or service (easy) that little vac valve.
Can someone please explain false pressure?
And this valve on the right is the vac valve you are looking for..

Beenbag wrote:Ahh ! OK, that wasnt clear from your first post, but if its only on "Start up" from cold then its a classic "false Pressure" situation as CSME9 said, caused by air trapped in the boiler after a cool down.
The most likely cause ir the vac relief valve on the top of the boiler, whose job it is to expel any trapped air as the boiler warms up. You need to replace or service (easy) that little vac valve.
Can someone please explain false pressure?
And this valve on the right is the vac valve you are looking for..
<image>

So I took the vacuum relief valve off tonight and I found the o-ring that's supposed to seal the valve nut has deteriorated to dust.



The actual valve mech seems to be good, but I'm assuming the bad o-ring seal is causing the issue. Guess Santa will be delivering a shiny new valve for Xmas!

Thanks again for the assist Beenbag & CSME9!

italoio78 wrote:So I took the vacuum relief valve off tonight and I found the o-ring that's supposed to seal the valve nut has deteriorated to dust.

<image>

The actual valve mech seems to be good, but I'm assuming the bad o-ring seal is causing the issue. Guess Santa will be delivering a shiny new valve for Xmas!

Thanks again for the assist Beenbag & CSME9!

If you can buy this valve and attach a silicone hose to drain back to the water tank or drip tray that will keep the inside electronics dry when the valve spits drops of water as it closes. Don't forget to wrap Teflon tape around the threads to seal the valve to the boiler.
https://www.chriscoffee.com/Vacuum-Brea ... p/f814.htm

Classic vacuum breaker issue. I keep a spare along with assorted gaskets in my parts bin.