Very basic question about how boilers work

stator

Some systems the heating may come on when your hot water is heating up, whether you want the heating on or not.

Having the hot water within the heatings timed periods is probably a good idea if you care about maximum efficiency, but I doubt it makes much difference.

Have you tried it just once per day? There may be enough hot water left for your shower in the morning if your hot water tank is insulated properly. Extra jackets are cheap to get if it isn't.

Geography_rox

stator said:

Some systems the heating may come on when your hot water is heating up, whether you want the heating on or not.

Having the hot water within the heatings timed periods is probably a good idea if you care about maximum efficiency, but I doubt it makes much difference.

Have you tried it just once per day? There may be enough hot water left for your shower in the morning if your hot water tank is insulated properly. Extra jackets are cheap to get if it isn't.

Thanks, unfortunately once a day currently (half an hour at 6ish am) doesnt last until the evening, but I didnt even know extra jackets were a thing so that's definitely something I will look into along with pipe insulation, thanks to all who suggested it!

Geography_rox

fergie_ said:

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.

Thanks for the explanation, so what exactly is the purpose of me letting water in every so often to get the pressure to 2? And what are the consequences of the pressure being allowed to go lower?

[Deleted User]

Below about 0.8Bars, your boiler will stop working. If you are having to top up the system pressure on a regular basis then you have a leak somewhere in your system. This could be from a radiator; a joint in a pipe or within the boiler itself. 

https://lcdheatingandgas.co.uk/blog/help-my-boiler-keeps-losing-pressure/

markin

2 bar is a little on the high side when cold, Apart from that green indicator do you know what it should be set to? If your putting it too high the safety valve may be opening and letting out water.

The temp dial also looks a little high, set it to around 1 pm and if the house takes too long to heat up slowly dial it up, And mark it with a pen when you find the sweet spot, Cold weeks may need an extra boost. 

Geography_rox

markin said:

2 bar is a little on the high side when cold, Apart from that green indicator do you know what it should be set to? If your putting it too high the safety valve may be opening and letting out water.

The temp dial also looks a little high, set it to around 1 pm and if the house takes too long to heat up slowly dial it up, And mark it with a pen when you find the sweet spot, Cold weeks may need an extra boost. 

Thanks, I have just gone by the green bar, but to be honest its on a rotating plastic cover so i have no idea which way round it should be! If i oeave the water on it settles at 2 hence why i went for that way round..

and yeah, when the heating is on i have it lower, i just have it high during summer so that the hot water gets hot with only half an hour heating. I have found that turning it down means the water isnt hot enough for showers and baths and so needs to be on for longer. I figure hogh intensity shorter time is better than lower for longer, but very happy to be corrected!

thanks to all who have replied to this thread, its so usefuk to finally have an idea how it all works. Every other part of everyday building maintenance and function is so easy to get info on, but I guess the sheet variety of types of boiler/heating combos mean I have always been confused

adindas

There are tons of infos on YouTube with illustration

https://www.youtube.com/watch?v=ddM7z-c7sUw

macman

Your tank is already lagged: the copper is covered with a coating of insulation at the factory. You can add a jacket if you want, it can do no harm.

FreeBear

QrizB said: 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.

I'll stick my neck out and say heating a tank of water will be a lot faster with the heating is off.

All the heat the boiler is generating is being fed in to the tank (via a heating coil). If the central heating is on at the same time, a fair chunk of that heat from the boiler is being used getting the radiators up to temperature.

xeny

macman said:

Your tank is already lagged: the copper is covered with a coating of insulation at the factory. You can add a jacket if you want, it can do no harm.

There's quite a good post here: https://lemonfool.co.uk/viewtopic.php?f=14&t=35513 about the difference in heat loss/gas consumption that adding a jacket made to a foam insulated tank. The poster talks about a payback time of around a month.