I have been reading with interest about the Londinium 1. I admit I am very much a newbie when it comes to spring-lever machines. Can someone explain to me how it is able to use a single boiler for both steam production and brew-temp water for the group and hot water dispenser?

I presently have a Silvia, and of course have to switch the thermostat back and forth when brewing and steaming. I understand how an HX system works, with the boiler always at steam temp and the brew water flowing through the HX to achieve brew temp.

But how does the Londinium work? My understanding is that the boiler is always at steam temp. Does boiler water flow into the group at steam temp and cool down sufficiently by the time it hits the puck?

Guidance appreciated.

gopherblue wrote:My understanding is that the boiler is always at steam temp. Does boiler water flow into the group at steam temp and cool down sufficiently by the time it hits the puck?

Yes, boiler water flows into the massive group head which cools it down to the brewing temperature. Key here is that group-head is at the right temperature so that boiler water can be cooled down appropriately. Works really well on Londinium and its really nice machine. You can't go wrong with it.

But isn't the "right temperature" for the group head going to be very subjective and vary depending on factors such as ambient temp, whether prior shots have just been pulled, length of time since machine turned on, etc?

What you say could be applied to any machine.

It's a commercial group so in theory it should maintain stability shot after shot.

The "right temps" could be more dependant upon your coffee. In any case, adjustment of the p-stat would be in order to dial in your preferred brew temp.

Currently, I have my lever running at 1.3 bar. Last month I had it at 1.1. I may adjust it again when I reload my grinder.

gopherblue wrote:But how does the Londinium work? My understanding is that the boiler is always at steam temp. Does boiler water flow into the group at steam temp and cool down sufficiently by the time it hits the puck?

My Elektra is a single boiler. There is an interior tube that feeds the group from the bottom while the steam wand is fed from the top.

I find that keeping the Group at temperature is easy and what Victoriacoffees says is spot on.

I suggest reading what is already Posted here on HB and what is being Posted on the Londinium Forum for the many questions and answers that might arise.

Forgot to add, that it is a HX thermosiphonboiler.

So if I understand everything I've read about the Londinium, it is not an HX machine in the traditional sense, but the thermosiphon effectively acts as an HX?

Here is the boiler and a photo of the interior of the boiler that shows the HX.