I have cleaned the venturi my problem seemes to be flow rate could it be a scaled domestic heat rxchanger on this excell 80 sp I have also changed the diaphragms as I was getting flow round the htg while in h/ wtr mode but this did not seem to work did I miss something.

Sam Glass, August 2010

that would be my next suggestion (the plate heat ex). if its restricted it may be forcing heat away. im not sure how effective cleaning it will be, woiuld suggest to replace

richard, August 2010

Richard I have fitted all parts from repair kit and still the htg comes on when ht/wtr runs and the ht/wtr is hot then cold this is caused because the boiler is running up to temp and shutting down on the stat I am about to remove the plate h/ex and wash it out will let u know the result. Sam Glass

Sam Glass, August 2010

replacing the diaphragms alone may not help. there is a service kit for these boilers which contain spindles and bobbins which operate in the divertor valve. what is the problem with it?

Richard, August 2010