Very basic question about how boilers work

Geography_rox

Hi, with winter approaching I have a very basic question about how boilers /central heating work. Basically I want to heat my water tank for about half an hour before a shower in the morning and half another half hour in the evening so the kids can have a bath. If I do that at the same time as the heating is on is it more efficient than when the heating is off? Does the boiler light a separate fire for the water that is independent of the heating or is it two circuits using the same heat source?

thanks a lot

mmmmikey

Commonly, central heating boilers have only one heat source and direct the heated water (directly or indirectly) to either the radiators or the hot water. There is some advantage in having the central heating and hot water on at the same time as the boiler works more efficiently like that, but I'm not sure how big that advantage is.

QrizB

There is only one fire.

Exactly how it works is different for a regular boiler or a combi. As you've got a hot water tank, you've almost certainly got a regular boiler. In this case the boiler heats water that can circulate through the radiators and/or a coil in the hot water tank, depending on  the settings.

It might be quicker to heat the water if the heating is off, but the efficiency will be pretty much the same whichever way you do it.

Geography_rox

Thanks a lot! Follow on question if I may, I have a red ball near my water tank with a pressure guage which I try and keep topped up at the right level as often as I can, but it loses pressure quite quickly (probably have to let more water in at least once a week when heating is on). Does this indicate a problem with my heating? And does a lower pressure affect the efficiency in any way? Thanks again, I find it very hard to find the answers to these basic questions on the internet in general!

Astria

Geography_rox said:

Thanks a lot! Follow on question if I may, I have a red ball near my water tank with a pressure guage which I try and keep topped up at the right level as often as I can, but it loses pressure quite quickly (probably have to let more water in at least once a week when heating is on). Does this indicate a problem with my heating? And does a lower pressure affect the efficiency in any way? Thanks again, I find it very hard to find the answers to these basic questions on the internet in general!

If you have to keep putting water in every week then I be wondering where that water is going - have you checked for leaks?

macman

Is this an unvented system?
Post a pic of the tank area and controls.

Geography_rox

Astria said:

Geography_rox said:

Thanks a lot! Follow on question if I may, I have a red ball near my water tank with a pressure guage which I try and keep topped up at the right level as often as I can, but it loses pressure quite quickly (probably have to let more water in at least once a week when heating is on). Does this indicate a problem with my heating? And does a lower pressure affect the efficiency in any way? Thanks again, I find it very hard to find the answers to these basic questions on the internet in general!

If you have to keep putting water in every week then I be wondering where that water is going - have you checked for leaks?

I havent seen any but tbh I havent looked that carefully, I guess I assumed it evaporated.. As you may be gathering, I have no understanding of how central heating works..

Geography_rox

macman said:

Is this an unvented system?
Post a pic of the tank area and controls.

I'm afraid I am not enough of an adult to lnow if it is vented or not, here is the tank and red ball..

Geography_rox

macman said:

Is this an unvented system?
Post a pic of the tank area and controls.

And here are the boiler controls

fergie_

The red ball is an expansion vessel. Its like a safety valve for the system and lets the system expand when its hot. It will have a pressure valve near it that lets air escape etc.

In answer to your original question, you will most likely have a set up where hot water is given priority. This means that a valve switches all the water to the storage tank from the boiler until it reaches the set temp. It then switches back to heat the radiators. There will be an advantage in that some water and the boiler will already be warm, but both parts of the system are unlikely to heat together.

xeny

From an energy/money saving perspective, it would probably pay you to spend £15 or so on an insulating jacket for the hot water tank and a few more pounds to insulate the pipework to reduce heat losses.