Citric acid concentration to gently clean (but not de-scale) boiler

#1: Post by **Paolo** » February 4th, 2022, 11:00 pm

I have a Lambro that recently has developed light brownish coloured water in the boiler (and also inside the sight glass).

I have drained the boiler several times and the water gets lighter each time and eventually runs clear...but the brown tinge comes back again after a week or so.

I have checked the spring and it is not rusting...in fact the brownish water doesn't taste rusty at all. There is no limescale inside the boiler.

I just want to give it a gentle clean inside without having to dismantle the boiler. As I am not after an aggressive clean, I was not going to heat the machine with the citric acid inside...just let the solution sit at room temperature.

Can anyone who has used citric acid to clean inside a boiler (whilst it is installed in a machine) recommend-
*the concentration of citric acid?
*the duration left soaking before removal and flushing?
*whether I need to neutralise (with bi-carb soda) the solution before I drain it (or the residue after it has just been drained)?
*whether any seals will get damaged by this gentle soak?

Many thanks.

#2: Post by **trumz** » February 4th, 2022, 11:57 pm

You might run into problems with desacling without removing the boiler. If you don't rinse the boiler very thouroughly after descaling you can get chunks of scale getting stuck in various places. If the boiler has a valve on the bottom to easily drain it, you might be fine.

10g/L is pretty standard ratio.

#3: Post by **miab** » February 5th, 2022, 12:25 am

That is probably coffee getting back into your boiler. Check your seals on your piston. Especially your bottom seal. Don't descale if you don't have to.