Hopefully this is a new topic, I couldn't find anything on this specific scenario.

I have a 2016 Londinium 1 bought used, and despite the boiler heating and pressurizing normally, the group will not heat up from a cold start. If I give it a flush, the thermosyphon kicks in and then it heats up just fine. If the machine is off but still slightly warm from previous use, it heats up just fine. I've tried flushing just before turning off the machine on previous use. Not sure what else I can try. Otherwise the machine works fine and makes great coffee. Funny thing is when I first got it, it was working normally, then for no apparent reason it started to do this. Any ideas much appreciated!

Randy

I've never experienced that on my Compressa. Have you posted on the Londinium forum or emailed Reiss? He's usually very quick to respond with useful ideas to further diagnose or fix issues, even if you are not the original purchaser.

Search for thermosyphon stall londinium and you should find some old threads. It was a common problem of the first version londinium. There were some mods that could be made to address the issue if I remember correctly.

Reaching out to londinium support is probably best.

Indeed, all the info can be found on HB.
When I had my L1, this would happen when I would do maintenance on the group and remove the piston while the machine was still hot.

There's a way to bleed the air trapped inside the thermosyphon by very carefully opening the port through the nut behind the group with the machine pressurized. You wanna ever so slightly unscrew it so it squirts water and releases air. I believe you have to do it a few times until you can't notice any more air coming out.

There's a video on this somewhere but I can't find it. You probably will by finding that thread on HB. It was quite a heated discussion back when the L1 was first released. Caused quite a stir. Was an easy fix for me. Wear gloves take your time.

I agree with CoffeeMac Tom regarding the Londinium site.. What you will find though is that you need to do an open flush after each pull of about 50 ml + to reset the thermosiphon process. I just count out about 4 seconds which is well over 50 ml.

The thermosiphon will often switch between the top and bottom pipes, this is normal too.

OMG... I totally forgot about the TS stalling when you don't flush the group after a shot. That's the minor stall. I went full blast to the major TS stall

To the OP... Try Mad Scientist's tip before playing with the nut behind the group.

Thanks everyone for the replies. The flush after shot does indeed solve the stall, which I knew already. My specific issue is that the thermosyphon isn't active the next morning when the machine starts up from cold, even if I flush after my last shot from the day before. It used to work but mysteriously stopped at some point.
If I give it a flush after boiler pressurizes that reactivates the TS and all works as it should. This is a problem for me because I start the machine on a timer and want it to be fully warmed up before I come down to the kitchen from my bedroom in the morning.

I did reach out to Londinium support and am emailing with Reiss. So far he has suggested venting the steam to see if it's a problem with the anti-vac valve which it's not. Then he asked for me to adjust the p-stat to a lower 0.8 to 1 bar instead of my current 0.9-1.2 bar. I wanted to do this anyway so I'm in process of making this change. He asked if my pressure gauge was at zero when machine is cold. It isn't, the needle is at 0.1 but I didn't think that was a problem as I've read others have that same thing.
I'll update this thread when I come to a resolution.

Mad Scientist wrote:I agree with CoffeeMac Tom regarding the Londinium site.. What you will find though is that you need to do an open flush after each pull of about 50 ml + to reset the thermosiphon process. I just count out about 4 seconds which is well over 50 ml.

The thermosiphon will often switch between the top and bottom pipes, this is normal too.

Perhaps I've not been flushing for long enough. I'll try this 4 second flush, thanks!

I have suddenly encountered the same problem as Randy struggled with in April. After years of coming into my kitchen in the morning an hour or so after the timer had switched on my L1 to find the group fully up to heat, now I find it is often only at 46C (at the point I measure) rather than the 80C I like for pulling shots.

Randy, did you resolve your problem? If so, I'd be grateful to hear your solution.

Matt