# Help with boiler safety valve compatibility



## soundklinik (May 31, 2013)

Hi and Happy New Year 🥳 to you all

this morning I started to de-scale my Isomac Tea ll.

When I do that I disconnect the fill up sensor so the boiler fills completely and overflows. Everything went fine until I blew fuses because overflow water that drains into drain cup was loose and water ran down over boiler and somewhere made a short circuit.

No problem, kind of expected that because after dismantling the BSV (boiler safety valve) and the drain cup I found out the plastic cup was "burnt " or just deteriorated.

It is not well designed IMO, if you have to sandwich a plastic cup between safety valve and boiler.

Solution would be a cup less system like the Rocket machine uses. However I don't know the size of threads on the Rocket. 
My machine has 1/4" BST. If it matched I could get rid of that ridiculous plastic cup and connect my overflow tube directly to safety valve 
Please see photos included. 
Thanks for any useful tips


----------



## El carajillo (Mar 16, 2013)

Providing the pressure setting is the same for both safety valves I do not see why you cannot change them over?

Are you sure the existing thread is BSPT. It does not appear tapered. Did the plastic cup act as a sealing washer ?? , was there sealing material on the thread ?

A soft copper washer and PTFE on the thread ??? Pipe to the drip tray ?


----------



## ken0062 (May 19, 2017)

Surprised you had any water coming out from the safety valve, I have a isomac millenium which has the same setup, if you disconnect the fill up sensor and overfill the boiler water will eventually pour out the anti vac valve which for some reason does not have a cup round it, safety valve should only release if you have over pressurised the boiler.

If you have a leak from round the thread of the safety valve you can cure that with plenty of PTFE tape on the thread.


----------



## soundklinik (May 31, 2013)

Thanks for replying both

I think that most of the safety valves have approximately same settings, around 1-2 bars so should not be a problem.

I am not sure about the thread, manual or parts list says 1/4 BST that to me is British standard threads. Correct? I don't think it's tapered.

The plastic cup was at one time part of seal and the safety valve had a standard fiber gasket . It's been a while I had it opened.

@ken0062 I watched many times the heat up process and as the pressure starts to build up it sputters a bit and maybe a teaspoon of water comes out into the cup and via clear plastic tube out to drain tray. On your machine it doesn't? Are we talking about same parts?


----------



## Rob1 (Apr 9, 2015)

The safety valve should only leak when the pressure exceeds whatever it's designed to open at (e.g 3 bar). The anti-vacuum valve will splutter and leak a drop on heating up.


----------



## El carajillo (Mar 16, 2013)

I think your first problem may be a faulty pressure stat, allowing the boiler to overheat and opening the safety valve

Age and burning of the contacts (P /stat) allow overheating. Has the M/ch been running very hot ?

If your water is quite hard the M/ch may need a heavy d-scaling


----------



## DavecUK (Aug 6, 2013)

This is the inside of an Isomac Tea I reviewed around 15 years ago. To the left of the cup (the brass thing) is the vacuum breaker, and it might hiss or even splutter when it warms up. Their main concern with the cup was to prevent water soaking the Giemmie box underneath the boiler if it ever let go, hence the cup and drain tube. it's why they wrapped the box in plastic. The vacuum breaker which arguably could have had a cup round it never did.

The safety valve should never hiss and leak, but there was a bad batch of that particular component you photographed in many manufacturers machines back in the day. The springs were defective, brittle and often would break. You could tell because they leaked a bit. You can fit any old safety valve with the right thread and a pressure 1.7 to about 2.3 bar. The cup isn't necessary, as it probably wouldn't have done much good anyway...but you can buy a new one if it's a feel good thing.

FI always thought the particular CEME pressurestat (black and yellow thing) they used was not a great choice and best replaced with a Mater XP-110. Just get the connections right.


----------



## soundklinik (May 31, 2013)

El carajillo said:


> I think your first problem may be a faulty pressure stat, allowing the boiler to overheat and opening the safety valve
> 
> Age and burning of the contacts (P /stat) allow overheating. Has the M/ch been running very hot ?
> 
> If your water is quite hard the M/ch may need a heavy d-scaling


 I think you could be right, I'm confused now...lol as long as I can remember, the machine always started the same way...you hear the heater kick in, then few bubbles, drops out of the safety valve that runs into the cup and down the tray. 
Machine doesn't run excessively hot but maybe a bit too hot. At the moment I don't have anything precise to measure the temperature of water. 
I only use high quality bottled water low calcium ~15mg per litre.

How do I test the pressure stat?

Thank you all for replying and helping 😃


----------



## soundklinik (May 31, 2013)

DavecUK said:


> This is the inside of an Isomac Tea I reviewed around 15 years ago. To the left of the cup (the brass thing) is the vacuum breaker, and it might hiss or even splutter when it warms up. Their main concern with the cup was to prevent water soaking the Giemmie box underneath the boiler if it ever let go, hence the cup and drain tube. it's why they wrapped the box in plastic. The vacuum breaker which arguably could have had a cup round it never did.
> 
> The safety valve should never hiss and leak, but there was a bad batch of that particular component you photographed in many manufacturers machines back in the day. The springs were defective, brittle and often would break. You could tell because they leaked a bit. You can fit any old safety valve with the right thread and a pressure 1.7 to about 2.3 bar. The cup isn't necessary, as it probably wouldn't have done much good anyway...but you can buy a new one if it's a feel good thing.
> 
> ...


 Thank you Dave, didn't see your post, I will probably change both, I think🤔 that few years back I changed a pressure stat but like I said I always remember this hissing and draining into the cup FROM pressure valve...

This morning I kicked the fuses twice 😂 as the basket let water through as I was descaling and overfilling the boiler


----------



## soundklinik (May 31, 2013)

So basically I shouldn't bother with the Rocket safety valve, (expensive)

instead I should get a new replacement safety valve and a new pressurestat?

Could there be faulty thermostat? IF it slightly overheats?


----------



## DavecUK (Aug 6, 2013)

soundklinik said:


> So basically I shouldn't bother with the Rocket safety valve, (expensive)
> 
> instead I should get a new replacement safety valve and a new pressurestat?
> 
> Could there be faulty thermostat? IF it slightly overheats?


 It doesn't have a thermostat, it has a pressurestat and a limit stat, that goes off around 150C ish, or lower as it gets old.

If it were my machine, I would get a safety valve, vacuum breaker and MA TER -XP110 stat, with and adaptor if your machine doesn't already use one...check thread sizes. As long as the safety valve is around 1.8bar to 2.5, you will be fine. The machines usually set at around 1.3 to 1.35 bar.

P.S Don't waste money on the rocketing in price safety valve.


----------



## DavecUK (Aug 6, 2013)

if the threads the right size, this would be good and you can fit the tube on the top of it

https://www.bellabarista.co.uk/lelit-bianca-safety-valve.html

https://www.bellabarista.co.uk/anti-vacuum-valve-1-4inch-long-pin.html


----------



## soundklinik (May 31, 2013)

Thanks for your help and links Dave


----------



## ken0062 (May 19, 2017)

Before spending any money on a safety valve I would replace the original one with plenty of PTFE tape round the thread and see how it behaves, once the cup gets cracked like your one it causes a poor seal on the OPV thread, the pic of your valve looks as if you have had steam escaping round the thread, same thing happened to mine and it gives the impression of a leaking OPV valve.


----------



## soundklinik (May 31, 2013)

DavecUK said:


> If it were my machine, I would get a safety valve, vacuum breaker and MA TER -XP110 stat, with and adaptor if your machine doesn't already use one...check thread sizes. As long as the safety valve is around 1.8bar to 2.5, you will be fine. The machines usually set at around 1.3 to 1.35 bar.


 Thanks, good idea, that's what I decided to do. Unfortunately I'm stuck with the rocket safety valve because my order got shipped and return would be too expensive.

I thought about the safety valve leaking and I remember that I replaced the pressure stat ONLY few years back...never the safety valve. And I think that was the problem all along. 
Do you know where is the vacuum breaker on my machine? I can't find it...embarrassing I know 😂


----------



## El carajillo (Mar 16, 2013)

To the left of the safety valve


----------



## soundklinik (May 31, 2013)

ken0062 said:


> Before spending any money on a safety valve I would replace the original one with plenty of PTFE tape round the thread and see how it behaves, once the cup gets cracked like your one it causes a poor seal on the OPV thread, the pic of your valve looks as if you have had steam escaping round the thread, same thing happened to mine and it gives the impression of a leaking OPV valve.


 I watched it bubbling from the top of the OPV and thought it was normal, thinking that it's the build up pressure that will close it, but it's actually the other way around, it should never leak but should release over pressure. I t was basically finger tight since the the plastic cup was totally burnt between the boiler and OPV.

Really hope I'll get it right this time. Thanks 😊


----------



## soundklinik (May 31, 2013)

This is my machine. It's the part with the 8mm hose connected right? On picture that Dave posted there is no connection to the right of XP 110



El carajillo said:


> To the left of the safety valve


----------



## El carajillo (Mar 16, 2013)

Yes the one with the plastic tube coming off. WHEN REMOVING. hold the "T" piece it is attached to ON THE FLATS just below with a spanner.

Failure to do this will cause the 'T' piece to rotate and loosen from the boiler necessitating removal from the boiler to reseal it with PTFE

Also take care when/ if you change the P/stat, hold the flats with a spanner. NOT GRIPS or you may / will crush / deform the fitting


----------



## soundklinik (May 31, 2013)

El carajillo said:


> Yes the one with the plastic tube coming off. WHEN REMOVING. hold the "T" piece it is attached to ON THE FLATS just below with a spanner.
> 
> Failure to do this will cause the 'T' piece to rotate and loosen from the boiler necessitating removal from the boiler to reseal it with PTFE
> 
> Also take care when/ if you change the P/stat, hold the flats with a spanner. NOT GRIPS or you may / will crush / deform the fitting


 Thanks 😊


----------



## soundklinik (May 31, 2013)

Thank you all for your help, greatly appreciated.

Well I'm up and running, finally I replaced the defective security pressure valve (thanks Bella Barista for all parts) with a sexy Rocket valve (only valve available at BB) that has overflow outlet on top so I could get rid off the burned out cup (pics above)

I changed old pressure stat for a new one, it cycles between 0.8-1.0. (I tuned it down) We never steam so I don't need much pressure in boiler. One thing I noticed new Pstat cycles much more often then the old one= (0.5-1.1, sometimes to 1.3 and was also set to 1.0)

I imagine it must be hard on the electric contacts inside Pstat...(I wish again to insulate the boiler, my last attempt failed by slowly "burning" the insulation material.

Regards Karel


----------



## DavecUK (Aug 6, 2013)

@soundklinik Two pieces of advice:



For the Isomac tea and all models with that size boiler, I would advise running no lower than 1.2 bar or you affect recovery time after the shot and adversely affect shot temperature after any cooling flush


You could always use the pressurestat to fire an SSR controlling the heating elemen, you just need an AC/AC switching SSR 20/30Amp rating heat sinked onto the frame.


----------



## soundklinik (May 31, 2013)

DavecUK said:


> @soundklinik Two pieces of advice:
> 
> 
> 
> For the Isomac tea and all models with that size boiler, I would advise running no lower than 1.2 bar or you affect recovery time after the shot and adversely affect shot temperature after any cooling flush


 Thanks @DavecUK 
OK, I didn't realise that, I will try that. Does that +0.2 bar adjustment raise temperature in boiler considerably?



DavecUK said:


> You could always use the pressurestat to fire an SSR controlling the heating elemen, you just need an AC/AC switching SSR 20/30Amp rating heat sinked onto the frame.


 Now that's really interesting...can you please elaborate on this mod, would it actually extend life of the pressure stat or what is the advantage? Doesn't the "spark" come from Pstat to SSR?....Since it's a relay, does the load go through SSR and not the Pstat?.. I think I don't quite get it

(I believe I have one SSR (and a PID) 
How would the wiring go? Pstat out >to SSR in|SSR out>boiler?...is there info/thread about this type of mod?

(One wire from Pstat goes to green lamp, which leaves 1+ and 1-)

Thanks for this idea, I will try to google it


----------



## DavecUK (Aug 6, 2013)

soundklinik said:


> Thanks @DavecUK
> 1. OK, I didn't realise that, I will try that. Does that +0.2 bar adjustment raise temperature in boiler considerably?
> 
> 2. Now that's really interesting...can you please elaborate on this mod, would it actually extend life of the pressure stat or what is the advantage? Doesn't the "spark" come from Pstat to SSR?....Since it's a relay, does the load go through SSR and not the Pstat?.. I think I don't quite get it
> ...


 1. from about 120 to 123.7

2. It would reduce the current handled by the pressurestat microswitch from 6 amps to around 40 mAmp or less. I can't tell you how to wire it, you need to figure that out for yourself...it's not hard.


----------



## soundklinik (May 31, 2013)

Thanks, I will try...


----------

