Combi preheat Good or Bad?!

bernie47

Hi guys

We have just had an A rated combi boiler fitted and it has the preheat function for hot water on it but is it keeps firing up every so often (every hour)?

I was looking at the gas meter dial and it was shooting round as the boiler fired up to do its thing but when you think of it, whats the point of this all day when your out at work and also when you go to bed it will do the same?

I would not say this is really energy efficient???

Any advice people

Cardew

It is the age old compromise of efficiency versus convenience.

One disadvantage of a combi is that it can take a long while for hot water to reach the taps i.e. depending on the length of the pipe run and given the time it takes to get the water supply to initially heat, you might need to 'run off' a fair bit of water before the hot water has reached a steady temperature.

Heating a small reservoir in the boiler largely overcomes this issue, but at the expense of keeping that reservoir up tp heat.

gas4you

I always leave pre-heat disabled on combi's I fit.

Running a bit extra water off is far cheaper than the boiler firing up regularly to keep itself warm.

The only other option is when a boiler has timed pre-heat. This could be set for the times you use most hot water.

bernie47

Thanks for the reply's guys!

It just got me thinking when i read this article on the net about combi's. (i cant post the link cos site wont let me):(

We have a Ideal Esprit 2 24HE boiler and i noticed it said on the LCD dial +1 hour, i think this is the pre heat function so i have turned it off now, it still fires up now and again but i may even think about setting up the timer for when we most use it.

gas4you

It would need to be a dual channel timer to have timed hw pre-heat.