Hello Allon,

This is the valve that I plan to use:

http://www.espressoparts.com/V_511A --- it is backordered at the present

http://www.espressoparts.com/V_511B is not backordered, but it is not certified, and appears to open at 2.5 bar.

Sorry, didn't know to call it a Boiler Safety valve, my mistake.

Thanks for your thoughts-
Joe

What "art" is, is beyond my pay grade, but he has expressed the desire to make a working machine.

You bring up an appropriate question. I don't recall seeing an expansion valve on any of those drawings of the brew circuit. Did I miss it?

I was talking about the valve on top of the boiler that opens up and scares everyone when the points in the pressostat weld themselves together.

I gotta be careful what I call these parts now, but I am planning to directly attach to the boiler:

1) A vacuum breaker valve;
2) A drain valve;
3) A pressurestat;
4) A Boiler Safety Valve;
5) A port to a pressure (0-3 bar) gauge;
6) A pressure tap to the gas regulator valve;
7) A check valve that is connected to the water fill manual pump, isolating the boiler from the feedline;
8) A steam line for the steam wand(s);
9) A water line to the water wand.

Parts not yet spec'd so no posting as of yet:

1) Thermostat (safety) on outside of boiler, sensing boilerplate temp: to cut gas pilot safety thermocouple if boiler runs dry (need to figure out how hot the set point should be and if the thermostat has NO nor NC configuration; I need NC.)

2) Thermocouple into the boiler - should this be in the steam or in the water? For monitoring purposes.

3) Water level sensor: if simple; I would put a probe in so that when water level fell below a desired level, a beep would sound. Would need to be simple and reliable, but plan at present is to watch the sight glass.

Plan for this to be another thread; after the boiler is mounted to the frame.
Joe

Ya know, if water weren't a scarcity, and you had plenty of fuel, you could make a steam powered pump which would multiply the pressure to overcome the boiler pressure (it's possible, if you don't mind inefficiencies) for charging the boiler...except it would also deplete your steam extra-fast with the cold water dropping the pressure at the same time.

Can you pressurize the tank that is used for charging the boiler? That might be easier than straight-on pumping when it's time to do the deed.

That doesn't solve the delivery pressure, but might simply things.

Water is a scarce resource when you have to haul it with you!

Pressurizing the tank is certainly an option-but if the ratio of air bubble to water is low (meaning small bubble and tank full of water to stop) you have to pump the air in frequently.

Until I prototype the pump I won't know for sure, but I think that each pull of the lever will deliver about 100 cc into the boiler, with about a 20 pound push of the handle. I am worried about how slow it is to refill the cylinder.

Joe

Joe,

I figured you'd have no use for the (elec) pressostat when you got the Astoria propane kit w/ it's gas pressostat.
So two pressostats (one electric, one gas), and some kind of thermal shutoff for the boiler endplate?

Also got me thinking about how much pressure those old s/s syrup tanks would hold. 150 psi would solve a lot of problems.

You might be able to get away w/o an expansion valve.

And I know you have already planned for an inlet valve for the boiler? Or was the check valve going to take that responsibility? Probably another good spot for something redundant.

Hi Norm,

I am concerned about how difficult it will be to adjust the Astoria gas valve; if I screw up, it could keep heating the water till something pops. The astoria valve has a pilot thermocouple in it- if the flame goes out, the thermocouple goes cold, stops sending juice to the valve, and cuts gas flow.

My plan for the pressostat was to set it high- say 1.5 bar - and try and keep the pressure at 1.3 with the astoria regulator. If the pressostat ever kicks high, it will break the circuit from the thermocouple to the pilot valve and shut off the gas.

The second thermostat was also in series between the thermocouple and the gas valve. I don't know how hot is hot, but I assume that if the boiler runs dry, it starts getting really hot really quickly. This thermostat should also break the pilot circuit and shut off the gas. I see that there are several possible thermostat temperature switch values. I need to learn a little more about what value to pick- but the idea is to cut off the gas if the boiler runs dry.

The check valve right at the boiler is redundant, but necessary. At the fill piston, there will be a pair of check valves - one to let water in, another to let it out. The latter may not be necessary if a check valve is attached to the boiler. If it were the only one and not attached right at the boiler, and the line leading from the piston to the boiler were to rupture, then hot water and steam would come flying out. Not good.

I really like the idea of the syrup containers at 150 psi, filled with water, and with 150psi bubble on top. An earlier idea I had was to use something very similar, (had forgotton about those stainless steel syrup containers- they would be perfect!) - but compressing the bubble with a cylinder of CO2 with attached 150 psi regulator. I need the CO2 for my wire burner anyway- and I figured that if the water had a lot of CO2 I could make crema all day long! It would be SOOO EASY to do it that way....

Joe

Joe,

There is a lot about this project i am not understanding but trying to be open to this "art" project.

It may not be necessary to adjust the gas valve at all. And certainly not difficult.
If it were me, I'd skip the electric pressostat and "thermal safety". The kit you bought is reliable and proven.

1.3 bar seems a little on the high side. I set my machine to about 1.1 or 1.2 bar for lower temps and increased machine longevity. I seldom steam milk. I understand I may be criticized for under extraction, "not the right temp" but between the very narrow ...... well, I don't really care, it's my own machine and I would prefer to under extract than over.
Also I believe LSM's are generally set to 1.1 or 1.2.

I always thought pressure relief valves were set to blow at 1.5 bar. But I suppose that varies with make. I know some of them are 1.7. 2.5 seems out of line for a pressure relief valve.

I would confirm what those s/s syrup tanks are rated for before I used one in that capacity.

I would also point out that there are magnets designed for actuating conventional 3 way solenoids (not for your machine) as well as 12v coils which *might* be adapted to your use.

Somebody else asked me tonight if I had an LSM leva group head.

More I think about this, the more baffled I am. But make it work and I'll be there for a double shot.

I agree 2.5 bar seems high for a boiler to is rated for 2.0 bar...
but here is the link to the supplier and the device:
http://www.espressoparts.com/V_511B

do you suppose that 2.5 bar is the maximum that it can be set for, and the installer is expected to adjust it to the desired (say 1.5) bar level?

I assume the 2.5 is a typo but you'd have to confirm that with the supplier.

And I'm very skeptical about the boiler only being rated for 2 bar. I'd have guessed 10 bar or more.