On Wed, 15 Nov 2006 10:06:01 -0800, Gravesy wrote:

Andy,

Thanks for your response.

I have looked at the pointers you made and have established the
following:

The boiler fails to light immediately when I attempt to draw hot water.
Sometimes it can take minutes to light other times it just doesnt and
rather than waste water we give up.

The diverter valve works fine and there is no hot water escaping into
the CH system when hot water is drawn.

The green light flashes indicating there is a demand for hot water but
the boiler does not light up. The fan runs as if it is about to fire
up.

I noticed this morning that the water temperature, when I eventually
got some hot water through, fluctuated from hot to cold.


I would say its odds-on this is the APS (about £40).

As a final check I would consult section 10.6 of the manual and look at
the value of parameter d.24 which is the return from the APS you will
probably see this moving form 0 to 1 and back even though the fan is
running all the while.

DO NOT take the APS out to check it will go down hard as you touch it, buy
the replacement FIRST.

The repair requires no tools. Simply turn off, remove the old unit
(accessible from above), swap the leads and tubes, and clip it in place.




--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards