Combi Boiler keeps firing up

[Deblc]

Hi

Can anyone help with these questions:

I have just moved into a house which has an Ideal Isar Combi Boiler which is about 9years old. It's serviced once a year and due a service now.

No probs with it at all, other than I have noticed that it keeps firing up even though we are not using the hot taps - or the cetral heating - like, throughout the night.

Is this because a hot tap is not turned off properly? (Even though we go round and 'turn' them all off) Could it be that we have a leaky or broken tap/not shutting off properly? (No drips from any hot taps to give a clue which one may be the problem though). Heating is completely off.

OR
Does this type of boiler keep firing up automatically to keep the water at a certain temp, even though you're not turning on a hot tap or ch?

Is it costing us money when it's firing up and we're not actually turning on a tap or anything? Had a huge gas bill, wondering if it's related to this?

I'm completely useless when it comes to this type of thing! Advise/comments welcome!
Thanks

 

[kirkgas]

when water is running through a tap a "D or d" is displayed on the front of the boiler, there is a pre-heat on it as well which is either an "s or a "5", (cant remember exact displays and this is the boiler i have )

 

[londonboy]

preheat is a 't'

 

[Agile]

Later boilers could have a modification to stop the preheat, older ones have to keep it.

It might add about £40-£50 to an annual gas bill.

A reasonable size house needs about £700-£1200 for gas bills.

A smaller flat about £500-£700

Tony

 

[mickyg]

an Ideal Isar Combi Boiler which is about 9years old

I didn't think they lasted that long

 

[gaspro1981]

i think that you can buy a preheat disablement kit to turn the preheat off not cheap tho

 

[londonboy]

i think that you can buy a preheat disablement kit

Yes they do one that fits on the cold main into the boiler.
Can't find its details on the internet though.