# Replacing a anti-vacuum valve on an Izzo Alex Mark 2



## jpt198 (Apr 28, 2013)

Hello everyone!

I have an Izzo Alex. Mark 2, that I bought here.

The other morning it was hissing, and steam was coming out a blue hose into the water tank.

After a bit of googling I believe that the anti-vacuum valve on the boiler is at fault. I found a discussion on how to fix this from 2007 (http://www.toomuchcoffee.com/viewtopic.php?f=2&t=5314), by cleaning or replace the valve. I have taken the value out, and opened it up (it has a ball bearing, with a small o-ring). I suspect that the part can be cleaned/repaired rather than being replaced, and that the o-ring has perished. I have included photos of the anti-vacuum valve (assembled and taken apart), to make sure I've got it right!

However, the o ring seems to be too small. I would expect it to fit snuggly in, held in place by squeezing into place (friction). Instead, it looks like it was stuck into place with an adhesive or something, but I can't imagine that's what it is. I think it's more likely to have slightly shrunk as its perished?

So, firstly, I wanted to check my logic, and that I have the right valve (and the right name for the valve!), secondly, ask for advice on buying o'rings (any material to look for, any brands to look for? Just measure the outer diameter, and the tube diameter? Ebay ok?) and finally, what part to buy if I need to replace the valve? (e.g. is this one ok? https://www.bellabarista.co.uk/espresso-parts/coffee-machine-parts-by-brand/ecm-parts/ecm-anti-vacuum-valve.html).

I haven't looked at the level fill sensor as the seam is clearly coming from the anti-vacuum valve.

Thanks for any advice!

Cheers

Jon

Images show: the faulty valve in situ with the blue hose, the where it was (once removed) and the whole and separated valves.


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## DavecUK (Aug 6, 2013)

O ring material can be silicone or Viton, EDPM is no good. You might want to state the thread size.


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## jpt198 (Apr 28, 2013)

Thanks DavecUK, good point!

Cheers

Jon


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## espressotechno (Apr 11, 2011)

It can be difficult achieving a leak-free rebuild. Just buy a new one, it's a standard a/v valve, they're cheap enough. Ebay is your friend....


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## jpt198 (Apr 28, 2013)

Great, thanks espressotechno, great tip.

I was looking for an "exact" replacement, and not able to find anything, great to know its a standard one... I like the rubber tube holder (although maybe only necessary with a leaking valve??), so looking for something similar - most don't have a 'barb' for a hose, but the gaggia one seems too... looking at a gaggia one (see ebay link below) - reckon that will do? otherwise I could get a standard universal one from bella barista (see second link)

Do I need to specify a pressure limit or anything??

thanks again for all your advice!

Cheers

Jon

https://www.ebay.co.uk/itm/Anti-Vacuum-Valve-suit-Gaggia-Coffee-Machine-Maker-1-4-BSP-Silicone-Hose/162121625876?hash=item25bf33b114:g:V30AAOxy-HtRXpBd&frcectupt=true

https://www.theespressoshop.co.uk/en/Universal-External-Brass-Anti-Vac-Valve-Tall-14---56150/m-2418.aspx


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## espressotechno (Apr 11, 2011)

Either will do. The espressoshop valve doesn't have a "splutter catch tube", but any start-up splutters soon evaporate from the boiler heat....

Use teflon tape when fitting.


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## jpt198 (Apr 28, 2013)

Hello everyone,

Thanks for all your advice. I managed to replace the valve with a gaggia one, and and very happy with it all!

Thanks!

Jon


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## El carajillo (Mar 16, 2013)

Makes a refreshing change when someone acknowledges the help they have been given.







:good:


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## jpt198 (Apr 28, 2013)

Hi again everyone,

I think I've done something wrong - firstly the valve lets at lots of water while heating up, and secondly, the steamer is squirting water!

Any ideas what it could be? I guess that theres water in the boiler, so while it is at the correct pressure (1.3 ish), it is too cold, hence the water rather than steam... wondering it I can adjust the valve (it has too parts with two hex head that can be loosened or tightened) - any ideas? I've tried to googled this, but no luck,

Thanks!

Cheers

Jon


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## DavecUK (Aug 6, 2013)

Sounds like the boiler has overfilled? Dont' try and adjust the valve, it's not adjustable.

Lots of useful information on the Izzo Alex here: http://coffeetime.wikidot.com/search:site/q/izzo

You definitely want to think about the Gicar box relocation when you get the boiler overfilling problem fixed.


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## jpt198 (Apr 28, 2013)

Thanks DavecUK, is that possible? I have no idea, but assumed that it was meant to be full or water?? should I try to drain it? turn the steam wand on and leave it to empty into something??

Thanks for the unadjustable tip! could I have bought one rated to the wrong pressure or something??

Thanks again!


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## jpt198 (Apr 28, 2013)

Hi DavecUK, sorry, just saw the rest of your message, will have a look at that link first... thanks. I think I might have been overthinking this!

Cheers

J


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## DavecUK (Aug 6, 2013)

The anti vac valve simply closes when the boiler gets a little above boiling, there's no pressure setting, it's either closed or open. The reason water comes out of it and the wand, is the boiler is too full. When you first heat it water expansion will push water out of the vacuum breaker, later when it boils the valve will close, but then the steam arm will blow lots of water out when you try to steam. In addition there is a good chance that as the water expands, if the vac breaker is pushed closed before it boils, then the hydraulic pressure might actually start causing the safety valve to weep water. If that happens enough times, then the seat can gunk causing it to leak along term.

If the boiler is overfilling there can be 4 main causes:


Calcified Autofill probe

Bad Wiring

Leaky autofill solenoid, e.g. when in the brew circuit position is letting water into the boiler with every shot

Gicar controller going bad.


You will have to test for each condition.


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