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DaveŁ
 
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On Sun, 17 Oct 2004 12:12:43 +0100, "Ed Sirett"
wrote:

On Sun, 17 Oct 2004 09:25:19 +0000, DaveŁ wrote:


A couple of times recently, the hot taps have been running cold, and
the combi boiler doesn't fire up when a hot tap is turned on in the
house.

I've also noticed a lot of air pockets blasting and sputtering from
the hot taps when thy are first turned on. The unheated water from the
the taps seems to be at a pressure high enough that would normally
cause the boiler to fire up - but the water is coming out ice cold.

The central heating is working fine.

The boiler is a Britony Combi 80 made by Chaffoteaux et Maury.

Anyone tell me what the problem is?

Many thanks,


For sure this is the HW flow sensor. I'm 99% sure this is implemented using a
differential pressure diaphragm on this model. The diaphragm has split or
the pin it move has jammed. Just possibly the microswitch it turns on has
completely failed.


Or - I think you might agree - it could just be that the water
pressure between the Secondary heat exchanger and the hot taps isn't
quite enough to trigger the diverter, yes?

I just increased the mains flow to the boiler, up to maximum (the
fill mains pressure), and found that I then got hot water from the
taps. The pressure at the taps was hardly noticeably different, but it
might have been just enough of a difference to switch the pressure
switch. Dos this sound feasable?

Dave L