Running GSH efficiently?

Ally74

Hi i have a question about the running of Gas Central Heating.

I will be moving into a new build mid terrace in a few weeks and it has gas central heating. It will be the first time i've used this heating system.

Some forum users will know i have an air to water ASHP system supplying 7 rads at the moment. I found the most efficient way to run this was to set the temp flow as low as possible (40C usually) so it was keeping the house at a steady heat without the thermostat having to click off and on.

Is it more efficient to run a gas central heating system the same way or is it best to keep the temp flow high as possible and let the thermostat do the job?

Any advice appreciated.

Ectophile

If it's a reasonably modern condensing gas boiler, then it will be able to vary its heat output to maintain the requested temperature.

If you're not sure, listen to the boiler as it runs. An old one will just cycle on and off. A newer one will gradually build up to full power, run like the clappers for a few minutes until the pipes are hot, then wind down the power to maintain the temperature.

I'm sure this thread will soon start a load of arguments about how you're supposed to run gas central heating, which will end up with discussions on physics and the laws of thermodynamics.

But my way to run gas central heating is to set the boiler temperature high enough that it will heat the radiators to your satisfaction in the winter. Too high and the room thermostat will just keep turning the heating off, too low and the house will never be warm enough.

That said, on a day that's just slightly chilly, the heating will still go on and off anyway.

Here's the bit that people keep arguing about...
The condensing bit of a condensing boiler works by pre-heating the returning water from the radiators, using the flue gases, before the water reaches the main heat exchanger. The cooler the incoming water, the better this works. So if you crank the boiler's temperature control to maximum, then the water in the heating system will get very hot, and the condensing heat exchanger won't do it's job properly. If you back off the temperature control to something more comfortable, then the boiler will work more efficiently.

Man_Overboard_2

What do you mean by 'efficiently'?

The most efficient way to operate any central heating system is to switch it off.

And then think about how to heat the bits of the house which actually need heating, and during which periods of time.

Ally74

Ectophile wrote: »

If it's a reasonably modern condensing gas boiler, then it will be able to vary its heat output to maintain the requested temperature.

If you're not sure, listen to the boiler as it runs. An old one will just cycle on and off. A newer one will gradually build up to full power, run like the clappers for a few minutes until the pipes are hot, then wind down the power to maintain the temperature.

I'm sure this thread will soon start a load of arguments about how you're supposed to run gas central heating, which will end up with discussions on physics and the laws of thermodynamics.

But my way to run gas central heating is to set the boiler temperature high enough that it will heat the radiators to your satisfaction in the winter. Too high and the room thermostat will just keep turning the heating off, too low and the house will never be warm enough.

That said, on a day that's just slightly chilly, the heating will still go on and off anyway.

Here's the bit that people keep arguing about...
The condensing bit of a condensing boiler works by pre-heating the returning water from the radiators, using the flue gases, before the water reaches the main heat exchanger. The cooler the incoming water, the better this works. So if you crank the boiler's temperature control to maximum, then the water in the heating system will get very hot, and the condensing heat exchanger won't do it's job properly. If you back off the temperature control to something more comfortable, then the boiler will work more efficiently.

Many Thanks,

It's a Worcester Bosch Group condensing boiler.

TiredGeek

Man_Overboard wrote: »

And then think about how to heat the bits of the house which actually need heating, and during which periods of time.

And we're back to that old chestnut

There are many sound reasons to want to heat ALL the rooms in your house even if you're not using them.

Damp and cold degradation of fixtures and fittings is my main priority, but there's also the fact that trying to heat one room to 20'c when the room next to it is ~10'c is harder as the heat transfers from the warm room to the cold room meaning you have to supply more heat to maintain the one room than you would expect.

OK, heating all the rooms is more expensive than heating a few choice rooms and maybe it's not for everyone, but the original question was how to use central heating most efficiently and turning it off isn't "using" it
If you want to take the argument to the extreme you could say that if you're not using all the rooms and therefore don't need to heat the ones you're not using, you'd be better off moving to a smaller house where you would use every room!

Ectophile

If you've got thermostatic radiator valves, you can set the warmth of each room, in addition to the main room thermostat.

I prefer to leave the radiators turned on in all rooms, but with the thermostat set to a lower level in the ones I'm not using. That should give sufficient warmth to prevent damp problems.

[Deleted User]

TiredGeek wrote: »

And we're back to that old chestnut

There are many sound reasons to want to heat ALL the rooms in your house even if you're not using them.

Damp and cold degradation of fixtures and fittings is my main priority, but there's also the fact that trying to heat one room to 20'c when the room next to it is ~10'c is harder as the heat transfers from the warm room to the cold room meaning you have to supply more heat to maintain the one room than you would expect.

OK, heating all the rooms is more expensive than heating a few choice rooms and maybe it's not for everyone, but the original question was how to use central heating most efficiently and turning it off isn't "using" it
If you want to take the argument to the extreme you could say that if you're not using all the rooms and therefore don't need to heat the ones you're not using, you'd be better off moving to a smaller house where you would use every room!

FB Like...

Some folk on this forum must live in mansions if they don't heat all their rooms. Selfishly I use all the rooms in my house... And heat them too, birch me now...

Ally74

jeepjunkie wrote: »

FB Like...

Some folk on this forum must live in mansions if they don't heat all their rooms. Selfishly I use all the rooms in my house... And heat them too, birch me now...

I'm the same, i will be heating most, if not all, of the rooms through the winter.

So this worcester bosch is smart enough to heat the return flow to the required temp of the thermostat as long as i set the boiler temp correctly?

Cardew

Ally74 wrote: »

I'm the same, i will be heating most, if not all, of the rooms through the winter.

So this worcester bosch is smart enough to heat the return flow to the required temp of the thermostat as long as i set the boiler temp correctly?

The boilers are not that smart!

As Ectophile explained well in post#2 for maximum efficiency you need the temperature of the water 'returning' to the boiler as cool as possible.

The boiler will modulate its output(i.e. turn down the wick!!). However even then, if the water temp from the boiler is very high, in some circumstances not enough heat will be dissipated by the radiators and the returning water will be too warm for maximum efficiency.

Conversely if the water temperture is set too low, in some circumstances the property will not get warm enough, or at least take ages to warm up.

TiredGeek

jeepjunkie wrote: »

birch me now...

I would, but you'd probably enjoy it

If you need birching for just heating all the rooms, what do I need? I'm heating an entire house I'm not using ROTFL

[Deleted User]

Dam, rustled again

Jeez... Heating a house you don't live in... Would burning at the stake qualify for RHI

Cheers