I performed a boiler descaling on my machine last night and its been behaving a bit strangely since. I have the machine on a timer for my morning and afternoon shots. Usually after 45 minutes the machine is nice and hot and after performing an HX cooling flush I start pulling my shots.

Today, when I ran water through the group head to cool I don't get the 'sizzling' water anymore - the water just runs normally. The boiler pressure gauge was in the normal operating range. I can get the machine to heat up properly by running steam through the wand. When I do that I hear a 'phumph' sound, like air is suddenly emptying, and the boiler pressure gauge drops all the way down - no exit steam. I then hear the sound of the boiler starting up again and the pressure gauge rising quickly. 5-10 seconds later steam starts to exit. After that the group head seems to heat up quickly and I get the sizzling water after a minute or so.

One other different behaviour I noticed is that the boiler seems to refill much more frequently than before - after drawing 6-8 ounces of water the boiler does a short refill.

Any thoughts or comments on what is going on are much appreciated.

Cheers!
Momo


Yesterdays process: I descaled by draining the boiler using the drain valve, then filling it up to the top with descaling solution through a funnel in the anti-vacuum valve opening. I turned the machine on for 20 minutes, ran the solution through the steam valve & group head and then let it sit for about 90 minutes. I then turned it on again and drew out the solution through the steam wand again and then through the group head. After about running about 1 liter of solution through, I turned the machine off and drained the rest of the solution out of the boiler and ran 6-7 liters of clean water to flush it out. The boiler refill did not kick in during the process. It had been 4 months since my last descaling.

It sounds like your vacuum breaker valve is sticking in the closed position. It's pretty easy to take out and clean. There may be a rubber O-ring on the bottom of the valve that tends to stick to the bottom of the valve if it has any crud on it.

That could be it, I'll take the valve out and inspect it tonight.
Cheers!

Hello:

Al deHyde wrote: ... sounds like your vacuum breaker valve is sticking in the closed position.
There may be a rubber O-ring on the bottom of the valve that tends to stick to the bottom ...

I think that's it. I have a Junior D/1 and seen it happen a couple of times, but as Al deHyde says, it's easy enough to fix. Paul Pratt recommends using silicon 'O'Rings as replacements instead of the usual OEM viton ones, which he has found to last considerably longer.

See his page with explanations on vacuum breakers valves here http://www.espresso-restorations.com/va ... akers.html

Cheers,

CIV

Definitely your vacuum breaker. Your O-ring is probably rock hard from years of use and is stuck in the closed position, causing "false pressure". If you had scale on it, it would most likely not seal completely, leaving you with a little bit of steam/moisture showing up on the left side of the cup warming tray. By opening your steam wand you vent that pressure, and then everything works fine.

You have two options: 1) leave it on 24/7, or 2) remove the vacuum breaker, unscrew the shaft of the vacuum breaker, replace the O-ring (lube it with a little Dow 111), and re-assemble. #2 takes just a few minutes; 10 if you take a 5 minute nap.

While you have the top and side panels off, pull out your boiler fill level sensor and check for scale. If you have any, you might as well scrape it off while you have it open.

And you can see this for the proper o-ring:

O-rings & Copper Sealing Washers

And/or use the top half of this LM vacuum breaker valve available from Espresso Parts - http://www.espressoparts.com/

civ wrote:
Paul Pratt recommends using silicon 'O'Rings as replacements instead of the usual OEM viton ones, which he has found to last considerably longer.

See his page with explanations on vacuum breakers valves here http://www.espresso-restorations.com/va ... akers.html"

I was interested in this site too, but it is apparently no longer functional. Does anyone have an updated address, or is this Paul's site gone forever (espressorestorations.com seems to be a Marzocco-only site that doesn't have anything on it).

Hello again:

The link is correct and the site was live when I posted it.
But I can confirm to you that at this time (16:51 -03:00 GMT) it is dead, won't respond to ping or tracert.
No idea what has happened, the web is full of possible glitches (ISP server down, DNS down, power shortage, etc.)

--- edit start ---

Whois says:
Domain Name .... espresso-restorations.com
---
Expiry Date .... 2013-09-07
Organisation Name .... Paul Pratt
---
Organisation Address. HONG KONG

Admin Name........... Paul Pratt
Admin Address........ Hong kong
---
Name Server.......... yns1.yahoo.com
Name Server.......... yns2.yahoo.com

The domain has not expired, the name servers are from yahoo and they're are live, so it's probably some other problem.

--- edit end ---

I'm sure it will be up again later on or tomorrow at the latest.

Cheers,

CIV

Thanks civ. Will try it again later. Must be a temporary glitch.

Hey thanks to everyone for responding!! For some reason I was only notified of the first response to my post and was surprised to see that others had contributed.

erics wrote: And/or use the top half of this LM vacuum breaker valve available from Espresso Parts

I've since ordered a new vacuum breaker from Chris' Coffee and was waiting for it to arrive before I 'skinned' my machine again.

uscfroadie wrote:Definitely your vacuum breaker. Your O-ring is probably rock hard from years of use and is stuck in the closed position, causing "false pressure". If you had scale on it, it would most likely not seal completely, leaving you with a little bit of steam/moisture showing up on the left side of the cup warming tray.

Great observation. I previously noticed a little bit of rust on a few non S.S. pieces in that area and now I know where this is coming from.

uscfroadie wrote: You have two options: 1) leave it on 24/7, or 2) remove the vacuum breaker, unscrew the shaft of the vacuum breaker, replace the O-ring (lube it with a little Dow 111), and re-assemble. #2 takes just a few minutes; 10 if you take a 5 minute nap.

If it wasn't for the miser in me, I would leave it 24/7, also good for not tempt machines tendency to fail at startup. I've wrapped the boiler in thick glass wool insulation to keep the heat in but I'm still too energy conscious to keep it on all the time. I think I'll try #2 before I install the new breaker.

uscfroadie wrote: While you have the top and side panels off, pull out your boiler fill level sensor and check for scale. If you have any, you might as well scrape it off while you have it open.

Good idea. Not sure which one is the fill level sensor, I'll send a photo of the boiler ends next time its open.

Cheers!