Jake_G wrote:Boiler pressure forces water through the HX injector when the lever is lowered. When the lever is raised, the HX is sealed and the injector supply port on the boiler flooded, so the T'S circuit stays full. Lowering the lever with the boiler cold (no pressure) would indeed drain the HX down to boiler water level and introduce air.

Cheers!

- Jake

Hi Jake, thanks for your reply. My question is about the TS only. The direction of the TS when the machine is stationary. My Lambro has the same kind of TS and I always wondered what the direction is of the heat. I always thought the opposite direction because to me it seems there is no water at the top output of the boiler.

NelisB wrote: My Lambro has the same kind of TS and I always wondered what the direction is of the heat. I always thought the opposite direction because to me it seems there is no water at the top output of the boiler.

On a Lambro (open thermosyphon), I don't think much siphoning is happening at idle because the TS is open to the boiler and the top part of the TS is above the water/steam line. What you have there is a steam heated group where condensing steam in the group causes a flow, with water returning to the boiler via the lower tube from the group.

See the picture below:

Water/steam level is appx at the blue dotted line, and the group's two TS tubes are at the red arrows. Water feeds the HX-like dipper tube at the green arrow.

Once the piston is raised above the inlet port (lever is lowered) the boiler pressure forces water into the both group tubes in the same manner as a conventional dipper with two siphon tubes.

After the shot is pulled, and the pressure is the same in the group as in the boiler, you have rising steam and sinking water in both the boiler and in the TS, which are open to each other, which will cause the water/steam line to find the same level in the group/TS and the boiler.

I *think* the original L1 mightwork similarly, although I believe they added a check valve on the boiler feed tube at one point which would tend to keep the water in the TS from draining back into the boiler.

Even on a conventional E-61 thermosyphon, condensing steam can be more effective at transferring heat to the group than thermosyphoning water. On my machine (a Giotto Evo, at ~1 bar, with a 3mm restrictor) my group normally idles at around 203F. However, if I lift the lever part way, opening the brew valve and not engaging the pump, and allow water to drain from the group and upper part of he HX, then close the lever, I now have a steam heated group, and my group temp will slowly climb as high as 220F.

Edit addition: Others (including I think Paul Pratt, who is certainly expert) say that the upper part of the group and TS tubes are full of water, not steam. My opinion is that the hole down near the element allows enough steam to first break the thermosyphon, stalling the heat transfer, then accumulate enough steam to become in effect a heat pipe thermosyphon, where heat transfer is via condensing steam at the top of the group. Makes sense to me, but I can't say for sure I'm right. It would be consistent with a group that never goes cold in a stall. Either way, the top tube would be hotter than the bottom and water would flow down the bottom tube.

In a saturated system the energy in a given mass of steam is considerably higher than the same mass of liquid and when the steam condenses to liquid that energy is given up to the surroundings. A true thermosiphon is using liquid only.

homeburrero wrote:On a Lambro (open thermosyphon), I don't think much siphoning is happening at idle because the TS is open to the boiler and the top part of the TS is above the water/steam line. What you have there is a steam heated group where condensing steam in the group causes a flow, with water returning to the boiler via the lower tube from the group.

See the picture below:
<image>
Water/steam level is appx at the blue dotted line, and the group's two TS tubes are at the red arrows. Water feeds the HX-like dipper tube at the green arrow.

Once the piston is raised above the inlet port (lever is lowered) the boiler pressure forces water into the both group tubes in the same manner as a conventional dipper with two siphon tubes.

After the shot is pulled, and the pressure is the same in the group as in the boiler, you have rising steam and sinking water in both the boiler and in the TS, which are open to each other, which will cause the water/steam line to find the same level in the group/TS and the boiler.

I *think* the original L1 mightwork similarly, although I believe they added a check valve on the boiler feed tube at one point which would tend to keep the water in the TS from draining back into the boiler.

Even on a conventional E-61 thermosyphon, condensing steam can be more effective at transferring heat to the group than thermosyphoning water. On my machine (a Giotto Evo, at ~1 bar, with a 3mm restrictor) my group normally idles at around 203F. However, if I lift the lever part way, opening the brew valve and not engaging the pump, and allow water to drain from the group and upper part of he HX, then close the lever, I now have a steam heated group, and my group temp will slowly climb as high as 220F.

Thanks Pat!

Sorry for highjacking the topic. But how do I lower the brew water temperature on my Lambro? Even if the pressure is beneath 1,0 bar, water exits the group at 100C. Group temp itself is not very high, beneath 80C. A TS restrictor would only lower the group temp, not the water temperature. Right? I would like to install a heatsink to cool the water before it reaches the group.

I'm only guessing here but if you install a flow restrictor in the TS then the group will run at a lower temp which will inevitably affect the brew temperature.
Flushing and measuring water temp does not precisely indicate brew temp since the water does not stay in the brew chamber as long and does not go through the coffee puck.
Does this sound accurate...?

Did I just highjack my own topic??

You bought the L1 used? Perhaps the previous owner used tap water with lots of minerals. I'm curious to see if cleaning the thermosyphon fixes your problem.

LObin wrote:Isn't the B3000AL an amazing machine or what!!

Indeed it is! I like it a lot, and it has now found a place in our office, thankfully. Our kitchen is a bit too crowded too for it. Sent it to repair/refurbishing earlier this year, and yes, milady ElisaBez is back in style! The best espressos I have ever had, minus maybe one or two with the ES3, are the ones I had with Bezzie.

NelisB wrote:Thanks Pat!

Sorry for highjacking the topic. But how do I lower the brew water temperature on my Lambro? Even if the pressure is beneath 1,0 bar, water exits the group at 100C. Group temp itself is not very high, beneath 80C. A TS restrictor would only lower the group temp, not the water temperature. Right? I would like to install a heatsink to cool the water before it reaches the group.

Who can better explain it than "Master Doug"

I suggest to watch these: http://www.youtube.com/watch?v=c6CWzFDHKXM and http://www.youtube.com/watch?v=xzHoLFon-ss.

Nelis, the group is your heat sink!! Water entering the group has of course a higher temperature but should lose the excess of energy to the group during preinfusion...... (also don't forget the coffeegrounds are cold and also take up some energy). And please, don't mess with your Lambro , one of the best vintage machines you can have at home......., if you don't like it, you can always sell it on -as is-
BTW the whole thermosiphon is filled with water when the machine is on; the vertical HX in the Lambro makes the top inlet to the group always the hot side; Contrary to the Londinium v1.0 where for the horizontal HX it actually doesn't matter that much which side is the hot/cold and it is known to switch from time to time the direction of the thermosiphon. I don't know if the same is true for Londinium R.

Enough High-jacking.....

One image is worth a thousand words...


Not perfect yet but very drinkable!

The thermosiphon was obviously blocked so my L1 was running cold. The hand test is obviously not very reliable...

Thanks to all the suggestions and the contributions to this topic. Excited to see what kind of results my L1 can produce!

Cheers everyone!