Kettle descaler in a heater matrix?

[gs.davies]

Yes or no? Any reason I shouldn’t use this to flush the matrix out? Any other methods for cleaning a matrix out?

[InnoCooperExport]

It's worth googling if any of the constituents don't affect the brass or brazes. I don't know exactly what's in these things so hard to judge...

[AndyB72]

I've used dishwasher cleaner and steradent tablets before with good results.

[snoopy64]

I’d start with a good mains pressure hose in both directions first and see what comes out…kettle descaler is ok as long you don’t leave it for hours and you rinse well. It’s also less aggressive when cold which is good

[gs.davies]

Well I’ve run a hose through it before and water went in and came out. I’d expect it to do that but I don’t know how much scale or sludge is in there. What would the capacity of a recirculating matrix be? Would that be a way I could measure if it’s full up with sludge?

[Peter Laidler]

I did one for a heater refurb project on this very forum. The matrix was 99% blocked with 10 years worth of dried-in shi....... er..., crap, rusty sludge and limescale. Filled it up as best possible and left it in a tub of 50/50 bleach and water overnight. After the 2nd night with a new bleach mix it was shite-free and is now running in the refurbed plastic heater in a happy Forumers mini clubman!

Just another thought. The IN and OUT of the heater matrix are at the same end. The trouble with that, as I found out, is that you can put a steady stream of water IN and a steady stream of water will flow OUT. The trouble is that the steady stream of water IN, IS NOT getting to the other/opposite end of the matrix where the shite and clag is sitting undisturbed. The bleach solution cured this.

On the second plastic heater I refurbed as a forum project, I drilled a 3/8" (?) hole in the other end to prod and poke the clag loose AND to pour the bleach solution in. Easy to soft solder a patch later.......