Removal of sludge from boiler without full system flush

[gas4you]

I thought I'd explained that clearly in my post earlier

 

[wizardsaleem]

It is a very common problem for Vaillants to collect 'sludge' in the HE coils at the bottom.

Usually this shows itself in a horrible droning noise when the boiler is run on full power.

You can isloate the boiler from the heating system via the valves under it, then attach a 6mm rubber pipe as a drain on one of the drain offs, pressurise the boiler and back flush just the HE, into a bowl.

It will be best to run the boiler whilst doing this and to also run a hot tap, so the plate HE gets flushed as well,

The plate HE, otherwise, will just act as a store for more sludge to return later.

I agree that fitting a magnaclean is a very good idea, as is Mickyg's statement about a proper flush of the system.

The above, however is a way to acheive the limited cleaning you asked about.

I have carried this out several times now, sometimes adding X200 after the HE has been cleaned.

Thanks,

You mention for a certain process "attaching a 6 mm rubber pipe into one of the drain offs" but the only drain off I know is is under the floorboards in the hallway downstairs. The boiler is sited upstairs in the bathroom. I appear to get an impression that there could be some more drain offs on or near the boiler which I could use. Would you please explain.

 

[gas4you]

There are 2 drains built into the ch isolating valves that the 6mm rubber (manometer tubing) will fit over.

You then need a 7mm spanner to open them on the square 'nut'.

 

[David937]

Don't forget, X800 in an aluminimum HE is a maximum of 3 hours.

We have about 5 Vaillant's in our family which all have a SS HE, only the two Ideals and the Biasi will have aluminium...I think.