Another Vaillant boiler problem

[mtecally]

Thanks.

looks like i will do this tomorrow night.

Ps I assume that i will have to drain down the full system for this.

Hi

As advised i removed the plate heat exchanger and flushed through,there was certainly a fair bit of foreign matter in there.

The hot water does now reach a good temp with the flow from the tap at about 50% and the noise that seamed to be coming from the main heat exchanger has gone

However if the tap is opened up more than 50% the temp on the boiler rises to 86 then cut off as before.

Any suggestions welcome

Thanks