Ferroli Modena 102 - CH but no DHW

[philjh]

Hi

The DHW on my Ferroli 102 does not work independently of the CH.

The LED does not light and no ho water is pruduced at any temperature.

Hot water is produced, however, if I start up the CH via override or if the CH happens to be on anyway.

Once the CH is truned off, then my DHW stops again as well.

I have tried giving the sensor a basic clean and also the green and yellow wired connector at the rear of the copper wiring block by the fan (an engineer showed me this a couple of years ago as I had intermittent hot water problems back then and this solved it, as it did last year, as it was just dust build up). This year, alas, my little fix is not working and it isnt even an intermittent problem anymore!

I can cope for now by using override to fire the CH is I need hot water but this is really only a short term solution so any advice would be greatly appreciated!

Many thanks in advance.

Regards

Phil

 

[Agile]

Have you done the normal first check with that symptom of measuring the resistance of each NTC sensor ???

Tony

 

[ollski]

or even just swap the wires on the sensors over to check.

 

[cross thread]

when u turn on the tap is the demand light illuminating? if not then flow switch will be the most likely fault

 

[philjh]

Thanks for the response everybody.

The demand light doesnt come on at all.

Ive no electrical/plumbing background, all Ive tried to do is what I have picked up over the three years of owning this hugely unreliable boiler (!) so havent swapped sensors in case I broke anything but I will try that if it is fairly foolproof. I`ve had a look on ebay and I can get a new sensor for about a fiver I think, and it seems a straightforward replacement job, unless I have missed something!

Would not know how to check the resistance if I tried! Any advice would be greatly appreciated!

Thanks again.

Regards

Phil