A while back I read a post on this site recommending periodically draining a boiler to help in the fight against boiler scaling.

After reading this I blindly added draining my steam boiler to the list of scheduled monthly maintenance steps since it is so easy to drain the steam boiler on my Vivaldi S1V2.

However, in hindsight I must admit that I do not fully understand how the mere act of draining the boiler helps in the fight against scale, unless it is assumed that the scale will "fall off" the heating element during the draining process.

Can someone please explain the reason why and how draining a boiler helps in the fight against scale?

Please note that I am not interested in spawning yet another "water/taste/TDS/hardness/scale" discussion, I am merely interested why draining a boiler should be on my list of periodic maintenance tasks...

Thanks,

Cor

When you steam milk, you vent steam out of the boiler, which exits as much purer water than it likely entered (assuming you're not using virtually-zero hardness water) in the steam boiler. The scaling minerals remain dissolved in the steam boiler water, and act to increase the hardness of that water. This accumulation of hardness in the boiler can turn a boiler full of water that is non-scaling into scaling water, if you don't drain it. That's my understanding. I thought it was mentioned in the Water FAQ, but I didn't find it in my quick skim.

Beyond that, hot water sitting in a copper boiler being repeatedly heated and cooled can take on funny tastes, for whatever reason. If you have a boiler that sees light usage, flushing will mitigate that. Of course, that's only an issue if you're using the hot water tap on the machine for a drinking application like brewing tea, coffee, or making americanos.

That is how I understand as well.

I believe it is more important if you don't use the hot water wand often. If you are someone who uses it quite often, flushing it could be probably be done less often.

I use my hot water wand for Americanos and my personal sized FP.. And Aeropress when I brew with it at home. I drain my boiler every 2-3 weeks.. Keeps my mind at ease.

Yep. water + minerals in; water only (as steam) out; implies that minerals accumulate in the boiler. So the boiler needs to be periodically drained of the excess minerals. Plant engineers call it "Boiler blow down," and they it need to do it very regularly, even for water that is treated with extreme, non-food safe chemicals to prevent scaling.

As Jeff says, if you frequently use the water tap, you are already flushing the boiler and don't need to do it as often. If you have a pour over machine, the easiest thing is to fill your tank with distilled or demineralized water, and run the water tap until the boiler is mostly refilled with it.

The Elektra T1 instructions recommend running the water wand 5 times for 10 seconds each and one liter of water through the group after the machine sits for over 12 hours. I assume that is so the machine produces less scale.

Fullsack wrote:The Elektra T1 instructions recommend running the water wand 5 times for 10 seconds each and one liter of water through the group after the machine sits for over 12 hours. I assume that is so the machine produces less scale.

I had thought that was more for commercial use of the T1. I've certainly not done this (or even close to this) for the last year. At some point I should check out what the boiler looks like inside. I suspect fine given that I steam on average less than 3 lattes a day.

Mark

The flush recommendation is also on a sticker placed on the side of the new T1 machines as well as in the instruction manual, so they seem serious about having users perform this task, though the reason could be something other than scale. Brass, in its present form contains some lead and from what I understand, the State of California is planning to outlaw it sometime in the future. Maybe this is a get the lead out exercise.

edit: The Semiautomatica manual doesn't include the flush recommendation.

My 1993 T1 had virtually no scale in the boiler, the HX tube was another matter, loads of the green stuff. I wouldn't bother inspecting the inside of the boiler until we find out the reason for the flush recommendation.

The older ones shine up nicely.

mhoy wrote:I had thought that was more for commercial use of the T1. I've certainly not done this (or even close to this) for the last year. At some point I should check out what the boiler looks like inside. I suspect fine given that I steam on average less than 3 lattes a day.

Mark

Fullsack wrote:...I wouldn't bother inspecting the inside of the boiler until we find out the reason for the flush recommendation.

I emailed Stefano and asked, "Do you know why the T1 instructions recommend an HX and group flush after the machine has been idle for 12 hours?"

His response:

"Just like any heating exchanger machine it will have the tendency to overheat while idle."

Takes 12 hours to overheat? Okay.

The instructions also recommend this procedure before using the machine for the first time, must be for a different reason.