Worcester 28CDi Hot water issue

[phile]

Hi people,

I have had the boiler for nearly 12 years (credit to Worcester)!

Last year I had an issue with the Diverter Valve so I replaced it and no problems, at the time due to the age I also changed the Overheat sensor, CH Sensor and DHW Sensor. All running fine.

Roughly 1 month ago the flashing red Light (Hot water LED) started flashing, after some investigation I changed the Air pressure switch and the hoses, problem fixed.

I'm now suffering with a Hot water issue, when running the hot tap it gets very very hot then the boiler ignition light goes out, this then repeats itself. The only way I can get it to run is if I turn the dial down on the front to 1/4 (min side).

The CH runs fine as does the Fan, do the think the DHW sensor has gone faulty?

Your Ideas would be apprieciated

 

[ollski]

Probably, but the other things to check are your plated heat exchanger for blockages and your gas valve modulation.

 

[phile]

One thing I forgot to mention...

When the dial is set mid way and the hot water gets hot the gauge starts to fluctuate.

 

[mickyg]

blocked plate heat exchanger.

 

[phile]

Well,

Just changed the DHW Sensor, no joy

But thanks to MickyG I gave the Exchanger a good whack well a few taps with a screwdiver and a spring clean with the hoover (don't tell the wife and what would you know shes running fine

Many thanks for your help

What would we do without forums

 

[bengasman]

Got a feeling he'll do an Arnie.