Don't understand our boiler! :-(

martin2345uk

Hi all,

We've just moved into our first home :-) but are having some confusion with our boiler... we have found an online manual but it has only added to our confusion!

It's a combination boiler - now I understood that these heat the water on demand as you turn on the hot tap.

If that's the case how come it has a setting for hot water, either "all day" or "timed"?

The manual recommends all day setting - does this then mean the gas is beng used all day instead of just when we use hot water?

Also, we've so far had it on auto, which means the hot water is "on" for 3 separate periods each day. This being the case, can anyone suggest why, outside of those times, the water is still warm (though not hot)? Surely if it heats the water on demand and the "hot water" is not on, it should be cold?!

Totally confused and welcome any advice / input!

NeverEnough

My understanding of combi boilers is that the hot water setting can be left on all day - not timed- and that you only use gas when drawing hot water. No need to put it on a timer, didn't think combis had a timer for hot water.

The timer setting is generally for the heating - ie central heating radiators- when you can set them to come on /off as you need, in which case the gas will be used during that time that they are on.

anselld

When water is "on" combi keeps a small reserve of water up to temperature so that it comes hot quickly when the tap is turned on.

When water is "off" it will still heat water when tap is turned but it will be starting from all parts cold and hence will take longer to come hot.

mr.pj

When the hot water is on, on the timer its means that pre-heat is on. As anselld said its heating up an amount of water in the boiler.

dexterwolf

We have a combi and the water just comes on when you want it. The heating is set to timed and we what times we want it on and then when it should go off.

googler

Make and model?

vectistim

As the other replies, if your combi has a timer option for the hot water then it probably has a small tank, maye ten litres (vs a hot water tank c.110)

anselld

vectistim wrote: »

As the other replies, if your combi has a timer option for the hot water then it probably has a small tank, maye ten litres (vs a hot water tank c.110)

Not even 10L, it is just keeping the heat exchanger hot plus whatever water is inside that.

martin2345uk

It's a powermax 155x.

Thanks for all the replies - very interesting!

But surely to keep the heat exchanger hot all day it just be using gas all day...?

anselld

martin2345uk wrote: »

It's a powermax 155x.

Thanks for all the replies - very interesting!

But surely to keep the heat exchanger hot all day it just be using gas all day...?

Yes. However that is partly compensated by needing less energy each time you turn the tap on.

It is a compromise between efficiency and convenience. Most economical would be to leave it off all the time, but it won't use much if you time it to be on at the times of day you are likely to be using hot water frequently.

martin2345uk

Ok - that sounds a good compromise. We'll leave it on as timed, but maybe try and adjust the times to reflect our activities a bit more.

Thanks again guys - might be back in the winter with a "don't understand the central heating either" thread :-)