I can't say about the boiler safety valve (will ask), but here is the label that is on my boiler that says 2 bar:



The heat exchanger bottles are VERY thick and look like they could withstand a very high pressure, but the boiler wall feels to be made of rolled copper (not brass) and is quite thin - maybe 3/32" - very different than the boiler end plate. It does not look as sturdy as a air compressor tank that routinely is pumped up to 150 psi. I would not want to try to pressurize this thing to 10 bar. I believe that with a HX system, the only way a boiler would see that kind of pressure would be if the HX bottle ruptured and the high pressure pump started filling the boiler, or if the pressurestat AND Boiler Safety Valve failed and nothing else started leaking at the fittings.

Joe

I do see where it says 2 bar. In what context 2 bar is meant is unknown, to me at least, I don't read italian. But it doesn't make sense to me that the boiler might burst at less than 1 bar difference of its normal operating pressure. Not enough margin for safety. And as you well know, thats something in this litigious age, engineers give a lot of thought to.

BTW, My 2 group leva LSM has three exchangers, one heating the water for coffee in the top of the boiler and two keeping the group heads at temp. Way different than your FCS boiler. You cannot just bolt on a leva group head and start making coffee.

http://www.espressoparts.com/V_511B

Espresso Parts has corrected the labeling on this Boiler Safety Valve to open at 1.8 bar.

Good Call, Norm.

Looking forward to this Joe...I'll try to add some input but since that post of mine we've added more machines and are swamped with work. I might be able to help you with some smaller manual components.

Also if you can't find something you want that is in your head, chances are you'll find it at mcmaster-carr

Good. Probably help their sales too.

Any more insights as to what 2 bar means on the boiler plate? Think it could mean maximum operating pressure? As in what it will run at 24/7 indefinitely? As opposed to "burst pressure".

I'm curious too.

Norm,

I have seen that before. It is just a quality badge certifying the boiler has been tested to withstand 2bar and I see it as a reminder to not go over that (thus the 1.8 bar safety relief is the backup on most machines).

If anyone is concerned about the burner overwhelming the safety valve...there is a lot of surface area there. On larger boilers you will see multiple safety mechanisms so that during a catastrophic failure nothing major happens (tell that Elektra installer in the UK that!

Also those who have concerns about rigging an odd piston to your setup...just look at the Cimbali M20 with a water powered piston http://www.ebay.com/itm/ws/eBayISAPI.dl ... 224wt_1037 Boy would I love to tinker with that...it makes me certain I could create a segregated piston pressure system that would create a lever style profile.

Remember...the main problems with a pump is:
1) disturbance of the puck (low pressure pre-infusion took care of most of those issues)
2) Lack of proper profile as puck density tapers, flow increases instead of decreasing...exacerbated by a pump's brute force method of brewing.

On a side note:
The HX is a small line with a similar wall thickness and can easily withstand the 10 bar a procon or lever creates. The reason they supply steel reinforced supply lines on a procon is that the procon is designed to produce a certain level of flow and pressure. A bypass valve built in (or nearby on some units) recirculates some of the water back into the supply side of the pump and adjusting the bypass is what adjusts the brew pressure. Since you are feeding water back into that line, that line receives stresses and would otherwise fail much soon if not for the steel supporting it.


Not sure if I've been helpful....but I had fun hearing myself type.

I believe that PE may be for Pressure Equipment; either it's a rating, or the 2BAR is the maximum allowable limit for operation. Is the unit CE conforming?


http://en.wikipedia.org/wiki/Pressure_E ... _Directive
http://eur-lex.europa.eu/LexUriServ/Lex ... 120:en:PDF

(haven't had a chance to read it thoroughly, but I saw this:)

3.3. Marking and labelling
...
(a) for
all pressure equipment:
- the name and address or other means of identification of the manufacturer and, where appropriate, of his authorized represen­ tative established within the Community,
- the year of manufacture,
- identification of the pressure equipment according to its nature, such as type, series or batch identification and serial number,
- essential maximum/minimum allowable limits;

truemagellen wrote: If anyone is concerned about the burner overwhelming the safety valve...there is a lot of surface area there. On larger boilers you will see multiple safety mechanisms so that during a catstrophic failure nothing major happens (tell that Elektra installer in the UK that! :)

None of the three or four group machines I've ever worked on had anything more than a standard, single, pressure relief valve. The same as on a one or two group machine. Maybe you meant something other than an espresso machine.

truemagellen wrote: Also those who have concerns about rigging an odd piston to your setup...just look at the Cimbali M20 with a water powered piston :) http://www.ebay.com/itm/ws/eBayISAPI.dl ... 224wt_1037 Boy would I love to tinker with that...it makes me certain I could create a segregated piston pressure system that would create a lever style profile.

I was afraid to mention hydraulic machines for fear somebody might want one. Good way to use three times the water of a standard machine. May be very hard to find parts too.

truemagellen wrote: Remember...the main problems with a pump is:
1) disturbance of the puck (low pressure pre-infusion took care of most of those issues)
2) Lack of proper profile as puck density tapers, flow increases instead of decreasing...exacerbated by a pump's brute force method of brewing.

Really?

truemagellen wrote: On a side note:
The HX is a small line with a similar wall thickness and can easily withstand the 10 bar a procon or lever creates. The reason they supply steel reinforced supply lines on a procon is that the procon is designed to produce a certain level of flow and pressure. A bypass valve built in (or nearby on some units) recirculates some of the water back into the supply side of the pump and adjusting the bypass is what adjusts the brew pressure. Since you are feeding water back into that line, that line receives stresses and would otherwise fail much soon if not for the steel supporting it.

I can't think of any leva machines that pressurize the heat exchangers. In fact LSM is the only leva I can think of that uses heat exchanges at all. Most use a dip tube (or two) from the back of the group head straight into the boiler.

Procon pumps are not supplied w/ s/s hoses.

The excess water pressure fed back into the supply line is relieved by the very next rotation of the pump. Or 1/4 rotation?. I can't remember if those pumps use three or four vanes.
But those braided lines sure do make it easy to change the pump out, as well as handle the 150 psi the pump produces.

Hi Norm,

I haven't been by in a while. I see you are our resident internet expert dude...just don't let some of the dreamers get stuck in the box because of a wayward comment of yours...I see it on automotive forums all the time

1) I didn't say there multiple pressure relief valves per boiler. I was just referring to the pstat cut off and the overtemp sensor that shuts down the heating element. On multiple groups with multiple boilers that you can control they will obviously have one pressure relief valve per boiler.

2) yes it uses a ton of water...but my two shots a day in my kitchen isn't going to cause the 10,000 lakes around me to dry up. All the machines I currently have were collected and rebuilt are for home use. If you have any serious levers you want to trade for I will gladly trade any of my machines for the right machine.

3) Yes...I have all procon driven machines except the Faema. A constant pressure is NOT ideal...just search for Pressure Profiling on the site and read some posts about the old Italian engineers and designers.

As the puck extracts the fats/oils make their way into the cup and the density of the puck decreases. The pump machines keep the pressure up and you have small scale channeling near the middle to end of even the best created shot (does not apply to Slayer and new LM machines of course who have pressure control). A lever action will decrease pressure though the shot...slowing down the brewing near the end and extracting more flavor. Doesn't mean it is a better shot but now the best shots have more dynamic flavor (some prefer the flatter flavor so it isn't a right or wrong but rather a different approach).

Also the temp tapers as well...HX machines do this...Double boilers the effect is not so great.

4) I can see were you could be confused by this comment. I was referring to the line from the pump that travels through the HX to the brew head being under pressure.

The procon itself doesn't come with anything if you order it. Manufacturers use braided lines on the supply side.

Also I wasn't referring to a lever in this comment, am I missing something?

Besides the Rancilio Levas are fed by an HX and so is the Bezzera levers.

truemagellen wrote:I see you are our resident internet expert dude...just don't let some of the dreamers get stuck in the box because of a wayward comment of yours.

Jason,
Not resident, yet. Likely just passing through. But strongly compelled to yell out when the emperor has no clothes. I hope there is room here for diverse views?

If anyone is concerned about the burner overwhelming the safety valve...there is a lot of surface area there. On larger boilers you will see multiple safety mechanisms so that during a catstrophic failure nothing major happens

From my experience, the kind of safety devices I see, have nothing to do with how large the boilers are. If one manufacturer makes a 4 group with a thermal safety, the 1 group has the same feature. You did specifically cite "surface area" as a reason.

On a side note:
The HX is a small line with a similar wall thickness and can easily withstand the 10 bar a procon or lever creates.

Can I presume you meant "has" instead of "is"? And did you mean "lever" as in pressurising the water circut instead of a pump or leva as in group head?