Changing Steam Boiler Water on Lelit Elizabeth

Question for Dave
Does it matter which round you do the flushing of the steam boiler
?

Thanks Dave.
I was a bit confused as in the Tips you start by describing the flushing of the steam boiler with the steam on but in the ‘Do this check’ part you advise that the initial flush should be done with steam off.

This is how you wrote it:

First part

I tried this of course, it does work, I just like to be sure it does and that I understand exactly what it’s

doing, so I can explain it to you.

• Ensure steam boiler is on and up to temperature

• Press the hot water button and allow the water to flow until it stops

• When water flow stops, switch machine off

When I followed the process I ended up with 630 ml of boiling water from a service boiler that only

contains 400ml (at most 480ml), how can that be? Remember earlier I said that it premixes with cold

water destined for the brew boiler water, doing this makes the most of Elizabeth’s ability to run really

high steam temperatures! I call it Lelits Hot Water Maximiser system (HWM). It is how they make

the very most of Elizabeths two boilers with clever programming and a cold water premix

Then the check bit

Techspeak warning - how the programming works

You can skip this bit if you want, but read the next section because it has some important checks to do after

An essential check you should make

To avoid any slight risk of damaging the brew boiler element (I don’t like to take chances), the first

thing you should do before draining the boilers is

1. Switch preinfusion OFF for button 1 (you can turn it on again later)

2. Drain System as in video & described earlier

3. After switching Elizabeth back on, draw about 200ml water through the group using coffee

button 1

This final water draw refreshes the brew boiler water as well. After this your steam boiler has been

refreshed and you can forget about it for a few months.

I may be a bit thick but it seemed to me that the last bit, about the essential check, conflicts with the first part so I wonder if you really advise doing this first and then the bigger (600ml+) flush afterwards.

Maybe it doesn’t matter!

Understood but I have just copied the advice from the tips so I don’t think you need the machine to explain which way round the two cycles should be done - or doesn’t it matter?

I have copied the section from the Tips document below so you can see the whole advice in detail.

My confusion arises because it initially appears that DC advises doing the ‘big’ flush first and then the smaller check to fill the brew boiler (maybe not necessary if you have the newer Marax quiet pump) bit after reading the last section ‘a check you should do’ it might be that he meant the second part should be done first.

Copied text from the Tips sheet below

Refreshing the Water in the Steam (service) boiler

The steam boiler is really called the service boiler in professional circles as it provides the steam and

hot water service but not brew water. Although a lot of authorities have stopped coffee bars using

water from the steam boiler for tea and Americano coffee (or tried to), the name service boiler is still

commonly used.

We might need to refresh the water from time to time (every month or two), especially if the water

has a high total dissolved solids (TDS). e.g. softened water can have a high TDS even though it

doesn’t scale. Even using Lelit inline filter cartridge, the TDS of the service boiler will gradually rise

as a consequence of steaming….

The service boiler is quite small as far as steam boilers go at 600ml and it’s probably running at 70%

or even 80% fill, I won’t get too technical here as to the reasons why. This is great because it means you only have to get around 400 ml out to fully remove most of the water in the service boiler. I

know this is a bit technical, but stick with me.

When you draw hot water, with the steam boiler on, it actually premixes with cool water as it heads

to the brew boiler as stated in my review. This is to give a smooth flow because all the water comes

via the brew boiler which tempers the superheated nature of the water. It’s also important to

understand what is going on later. Just remember this, because it’s clever (as usual with Lelit).

2 - How to drain the Lelit Elizabeth service (steam) boiler

I tried this of course, it does work, I just like to be sure it does and that I understand exactly what it’s

doing, so I can explain it to you.

• Ensure steam boiler is on and up to temperature

• Press the hot water button and allow the water to flow until it stops

• When water flow stops, switch machine off

When I followed the process I ended up with 630 ml of boiling water from a service boiler that only

contains 400ml (at most 480ml), how can that be? Remember earlier I said that it premixes with cold

water destined for the brew boiler water, doing this makes the most of Elizabeth’s ability to run really

high steam temperatures! I call it Lelits Hot Water Maximiser system (HWM). It is how they make

the very most of Elizabeths two boilers with clever programming and a cold water premix

It’s also the reason why I could get 630ml of boiling water out of a service boiler only containing about 450ml. It works like this:

Techspeak warning - how the programming works

You can skip this bit if you want, but read the next section because it has some important checks to

do after.

I tested it of course and did a few tests so I could work out what the programming code is doing to

allow this to happen. It goes like this:

• Hot water button pressed

• Water comes out but heating element on

• Water level goes below level probe in service boiler (heating element switched off)

• Because water is drawn programming prevents autofill and steam boiler heating element

remains off

• residual pressure keeps pushing water out of the service boiler (remember that 2 minute

steaming video)

• Hot water system is on a timer so after a preset time the water flow is stopped (because they

worked out the service boiler is most likely completely empty). In fact in the old Elizabeth

you probably partially emptied the brew boiler as well. This is because the old pump had a

higher flow rate than the quiet X-pump.

I highlighted the last bit because it’s important and is the reason for a check I recommend you make.

An essential check you should make

I finished off the tech speak section with stating that the brew boiler might empty a bit if you have

the old pump and probably not with the MaraX pump. It also might depend a bit on how close the service boiler was to autofilling.

Brew boilers in most/all prosumer espresso machines do not contain level probes and have no way of

knowing their water level. In fact the thermostat on the Elizabeth brew boiler does contain a level

probe, because it’s a combined unit but it’s not used. That’s just the way all dual boiler machines are

designed at the moment. (note to self: see if one day Lelit can link brew boiler combined probe to

software, so heating elements can be shut off if water is low).

To avoid any slight risk of damaging the brew boiler element (I don’t like to take chances), the first

thing you should do before draining the boilers is

1. Switch preinfusion OFF for button 1 (you can turn it on again later)

2. Drain System as in video & described earlier

3. After switching Elizabeth back on, draw about 200ml water through the group using coffee

button 1

This final water draw refreshes the brew boiler water as well. After this your steam boiler has been

refreshed and you can forget about it for a few months.

Oops you’re right. I confused preinfusion with the steam (ie ‘e’ icon).

Apologies!

On further reflection I might have been right after all.

As Button One is usually set for preinfusion with the steam boiler on when the single press method (then displays ‘e’ icon ) is used this stops the preinfusion and the steam boiler is turned off.

It is all quite complicated when you look at the detail.

The essence of my question, which seems to have got lost in the complexity of the detail, was, if the check process was even necessary with the new Marax pump - which I have, which way round should they be done.

Is it 1 flush the steam boiler (turned on) yielding about 600ml plus then either turn off steam boiler (show ‘e’ icon) or go into the programming mode and set preinfusion to ‘0’ - not sure which - and flush 2-300 ml via the coffee boiler ( presumably using either coffee buttons or both together) or the other way round.

If you can put me right on this I would be very grateful as I am still confused.

Thank you that is very clear.

I assume that by ‘preinfusion off’ you mean set it to 0.

Thank you for your patience and helpful advice which is much appreciated.

All very clear now. Thank you for sticking with this in spite of my convoluted posts!