Raven Heat Combi Cut out...?

[Xengstu]

OK, went to change a diverter valve a Raven Heat Combi, can't remember the exact model but it was none condensing probably about 5 years old. After changing the diverter valve we get flame lock out after about 2-3mins of running the hot tap. Keep the tap running and boiler re-ignites and off we go again. Here's what we've done,

Checked for air in the heat exchanger
Checked for leaks in the burner box
Checked and adjusted the Burner Pressure (from 9 to 8) this helped a little but it still cuts out.

CH works fine BTW

With the previous faulty diverter valve heat was was being leaked to the CH circuit when there was HW demand. replacing the diverter valve has now highlighted (we think) an overheating problem in the heat exchanger. Currently running a cleaner through the system to see if its crud in there but we'll probably end up replacing the boiler anyway. Was just wondering what thoughts anyone else had?

Thanks

 

[HTB]

It was a crap boiler when it was made.

 

[Xengstu]

You be right HTB, not one of the finest boilers out there lol.

I was asking out of curiosity as i'm learning the ins and outs of all boilers. Plus it might actually help someone else out there... you never know?

 

[leakylea]

hot water stats can be a problem with raven heat little stars and r/heats in general, most probably heat exchanger blocking up, not even power flushing will guarentee a clean boiler. is the filter clean on the incomming suply? good luck!

 

[Xengstu]

Thanks leaky,

Thats the strange thing there was really good flow out of the hot tap and I couldn't get me head around why it would allow the heat exchanger to over heat???? you could hear the water starting to fizz then it would cut out. Pointless exercise with it being a Raven heat piece of **** I know but I would like to understand why...