secondary heat exchanger

[bullvine]

Hi to all, I have posted a question before on no hot water coming out of my potterton oil flowsure combi boiler. since then an engineer has taken the plate heat exchanger off and chemically cleaned it out. still no hot water, but the pipes going to the diverter valve are really hot. he did say that the main heat exchanger or the valve could be the problem. the system has been flushed out so many times I cant see it being the main exchanger.
Any help would be great and appreciated

 

[superdupergasman]

how does the heating work??

That would prove main heat exchanger was ok.

May be divertor jammed in funny position.

 

[bullvine]

The heating works okay just takes some time to circulate round the system. the temperature reading of the water starts at 60 degrees but as soon as you call for dhw the boiler cuts in then the temperature goes to 90 then the boiler will not cut in again until it goes back to 60. i manually lifted the switch on the diverter valve and I felt the hot water bypss and go through to the c/h pipes.