In looking at that pic I see the following:
Pump >> right angle fitting >> boiler

boiler goes to a small tee. One branch is to the manometer, the other goes to a larger tee.

The larger tee contains the steam adjustment valve (what OP called a 'regulator'). The opposite end looks like a bypass valve... for steam.

Here's the parts list. No OPV labeled. But you could certainly add one.

https://coffeemachineparts.com.au/index ... pare-parts

What do you surmise the steam bypass valve is?

It looks like an OPV.

It quacks like an OPV.

It may decide that it would prefer it if you called it a "steam bypass valve", but I have yet to be convinced that such a thing is actually a thing, so... why add something to a machine when it is already there?

A steam bypass valve that does not open until over 9 bar?

The steam relief valves in my uncle's home heating system (the old fashioned big radiators) open at 15 psi. I would imagine steam at 200+ psi would be radically dangerous. There's no way the pump OPV and the steam relief valve are one and the same.

It seems very unlikely there is a functional steam bypass valve on that machine that is set to some lower pressure than whatever the components would be expected to operate at. Are you suggesting the steam bypass opens at 1 bar or so, but only when the steam valve is open? What would the possible point of that be?

If you look closely at the picture...

It seems that order for the steam valve to work at all, the plunger is blocking the path between the boiler inlet and the steam wand. The "steam bypass valve" is on the boiler side of the valve body. When the boiler sees high pressure, so does that valve. So it must be rated for whatever pressure is shown on the gauge, which is attached to the tee fitting on the boiler.

I could be wrong, I just can't think of why one would go through the trouble of having a bypass valve specifically to protect the steam wand... like what's the failure mode you're worried about? A clogged steam tip would activate this "bypass"?

Sorry if I'm seeming argumentative, but this seems so obvious to me that I'm a little persistent in holding the OP use what they have to get what they want.

Also, 200psi (9 bar is 135 psi, but no matter) steam is not likely to be produced by a machine such as this. In order to produce steam, you must heat the water up to the boiling point. The snap thermostats on these machines are likely set to 125 or 135C, which means the the highest pressure you can have steam at is somewhere between 1.3 and 2.2 bar. Any pressure higher than that, and the steam condenses leaving you with only hot water.

Cheers!

- Jake

I'm not thinking about protecting a valve. I'm thinking about protecting users from the consequence of a buildup of too much steam pressure.

In any event, multiple folks have stated that the existing 'bypass' valve cannot be adjusted. If that's true, the OP would still need an adjustable OPV - unless the machine is already running 9 bar or so, in which case why bother?

It's not dangerous, the silicone hose routes it to the reservoir, rather than pointing it at the operator's face...
All SBDUs compress their steam to 9Bar when brewing.

That "Bypass Valve" would bypass whatever fluid, steam/air/water was in the upper section of the boiler when pressure exceeded 9 Bar (or whatever it was set to).

And as the Beatles sang in "All you need is Love"...
There's nothing you can burn that's not combustible... There's nothing you can adjust that's not adjustable. There's nothing you can say but you can learn how to feel okay... It's easy!
All you need is Love (and a wrench that's about the right size , perhaps a 10mmm) to turn the obviously hexagonal threaded end that holds the ball against the spring...

Yes, the other verses all rhymed better.

Isomac just wouldn't put THAT valve there, dress it up as a working OPV with the silicone hose and all, with the threaded part and then somehow disable it to make it non-adjustable. But, yes. I believed OP for a moment, too.

coyote-1 wrote:I'm not thinking about protecting a valve. I'm thinking about protecting users from the consequence of a buildup of too much steam pressure.

Ok.

Boiler safety valves set to a low pressure (2.5 or 3 bar is common) are prevalent on HX machines and dual boilers with a dedicated steam boiler, but with SBDU machines, they can't be implemented because the valve doesn't know the difference between steam and brew water. Thus, the OPV or bypass or safety relief valve, or whatever you want to call it must be set to whatever you wish to limit your peak brew pressure to. You can't have a separate valve that only works when steaming.

Here is the quote that matters -from a service tech who has worked on thousands of machines and hundreds of Isomac machines, and he knows what he is talking about:

That OPV is completely the opposite outlet from that tee-fitting, it has nothing to do with the steam wand side of that boiler outlet, it is functioning as an OPV to limit the maximum pressure in the brew circuit (the little brew valve on a spring will be lighter, thus it would effectively be the expansion valve).

In good news, it's definitely an OPV and it looks adjustable to me, examine it more closely. If it's still adjustable, it should be good enough. If it seems seized closed and un-adjustable, be gentle with it. Let us know how it goes.

And from Stefano, who has sold many thousands of parts and serviced just as many machines:

The Maverick should have the style of OPV integrated with the steam valve 0154 sku
you could potentially remove the guts from it (mushrooms and spring)
leave it fully open then add another one on line (we sell several ones and so do other vendors)

Stefano does suggest an adjustable OPV could be added, but that doesn't mean the existing OPV can't be adjusted. It may not be designed with a large adjustment range, but why not try?

The only other comment refuting the adjustability of the OPV is the OP, and their argument is... weak.

There is no adapter, therefore this OPV is non-adjustable.

I don't even know what this argument means.

The hose nipple on the OPV is threaded into the valve body. The end threaded into the valve is compressing a spring. The spring is pushing on a plunger. Loosen the nipple fitting a thread or two and voila - lower brew pressure. It is also entirely possible that the stock OPV is actually set to 9 bar, but the plunger is stuck closed. Opening the the OPV and inspecting it could well be all it takes to achieve the desired brew pressure.

Anywho, the OP hasn't logged in for the last 4 days, so this is all probably a moot point.

Cheers!

- Jake

I was not basing it on OP, but on others who have posted vids on this exact machine. From those vids it looks like it would be adjustable, but that a sealant has been applied which prevents that adjustment. And if that's the case I'd err on the side of caution. Why risk destroying your steam valve when you could add a pre-boiler OPV?

Jake_G wrote:
I don't even know what this argument means.
Cheers!

- Jake

All you need is love!
Love is all you need... (I really thought this stupid thread had ended last week). Thank you , Jake, you've kept me from getting rude in the replies.

Hi all,

It has been a tough week here. I am quite surprised with all the passion and the analysis provided.

I would agree, that the second part of the T-fitting might be adjustable, given the fact, that there is a threaded insert at the end. On the other hand; I would be cautious not to ruin the machine, in case the insert is somehow glued.

This part has been proposed to me. What do you think?

https://www.bluestarcoffee.eu/en/Vibiem ... -5613.aspx