Why is my gas likely to be costing so much all of a sudden?

B0bbyEwing

Jeez there's a ton to get through now. Not complaining. Actually saying thanks for the replies.

Since boiler has been mentioned ours is a Worcester Greenstar 30si. I'll take a look at that eco setting you mention. I've had a look & our rads are set to 4 where the taps are set to just slightly past e by the looks of it. Not as far as 6 but a smidge beyond e.

Scot_39

From the mark4 installation manual

https://www.worcester-bosch.co.uk/professional/support/literature/greenstar-si-combi-installation-instructions

"Pre-heat reduces the time taken to produce hot water at

the tap and is controlled by the ECO button.
B Press the ECO button to select either state:
– When the ECO button is not illuminated the boiler
will be in pre-heat mode (which will reduce the
time taken to produce hot water at the tap).
– OR
– When the ECO button is illuminated the boiler will

be in Economy mode with pre-heat no longer active"

Try turning on the eco mode. And looking at use again overnight when no demand.

Its basically AFAIK keeping a volume of water in and the heat exhanger itself hot - and so I guess on colder nights - in the boiler room - more likely to fire to do so.   

But even then not sure it explains the several kWh of use when not running heating or any HW.

B0bbyEwing

Just to update that pressing the eco button on the boiler clearly hasn't worked. 

Woke up 5:30am & there was £0.79 used (8.01kwh) since midnight. 

Had a look at the heat settings at the bottom of the stairs. Display read 14c & the heating is set to come on when it drops at 12.5c.

So I'll have to have a look at what temp it's set to kick in throughout the day & tweak where needed. 

Other than that it's turn every rad off when I go to bed & see what's used then. 

Magnitio

B0bbyEwing said:

Just to update that pressing the eco button on the boiler clearly hasn't worked. 

Woke up 5:30am & there was £0.79 used (8.01kwh) since midnight. 

Had a look at the heat settings at the bottom of the stairs. Display read 14c & the heating is set to come on when it drops at 12.5c.

So I'll have to have a look at what temp it's set to kick in throughout the day & tweak where needed. 

Other than that it's turn every rad off when I go to bed & see what's used then. 

If the heating has turned on because the temperature at the thermostat dropped below 12.5, then the boiler will fire up. If you have turned down all of the radiators, then it will continue to pump hot water around the pipework. It may even cause issues with the boiler/pump unless you have at least one radiator open. Usually you will have one radiator that has no TRV.

Depending on the boiler settings, thermostat controls and radiator sizes near the thermostat, it is quite difficult to maintain a temperature as low as 12.5 degrees, so it's possible the temperature will cycle between 12.5 and 14 degrees.

grn99

Other than that it's turn every rad off when I go to bed & see what's used then. 

Unless I'm missing something, I can't see this helping. If a roomstat calls for heat, turning off every rad will seriously reduce that temp being achieved, prolonging the time gas is consumed. If the boiler is firing for frost protection, that will still happen regardless of a TRV setting.

B0bbyEwing

Thanks for the info. I wasn't aware turning the rads down would make no difference. 

So this is likely due to it being around 0-1c the past few nights then, nothing more? 

grn99

I think that's certainly a possibility, depending on the boiler's location. From the manual, it says "If the temperature falls below 5°C within the boiler it will periodically fire to avoid the possibility of freezing." This is to bring the internal temp up to around 12C. It will do this cycling as often as necessary. Also, independently of the frost stat, if the room temp drops to the room stat value you've set at 12.5, the boiler would fire then too of course.

FreeBear

grn99 said:

Other than that it's turn every rad off when I go to bed & see what's used then. 

Unless I'm missing something, I can't see this helping. If a roomstat calls for heat, turning off every rad will seriously reduce that temp being achieved, prolonging the time gas is consumed. If the boiler is firing for frost protection, that will still happen regardless of a TRV setting.

Its a bit worse than that. Turning off some/all of the radiators reduces the load on the boiler. Once you go below the minimum output that the boiler is capable of, it will start to short cycle. This will knock efficiency right down as well as increasing wear & tear on the boiler.

Unless the boiler is located in a garage or loft, it would be better to turn it off at the mains - If the meter says gas is still being consumed, then the meter may be faulty (almost flat battery ?).

B0bbyEwing

FreeBear said:

grn99 said:

Other than that it's turn every rad off when I go to bed & see what's used then. 

Unless I'm missing something, I can't see this helping. If a roomstat calls for heat, turning off every rad will seriously reduce that temp being achieved, prolonging the time gas is consumed. If the boiler is firing for frost protection, that will still happen regardless of a TRV setting.

Its a bit worse than that. Turning off some/all of the radiators reduces the load on the boiler. Once you go below the minimum output that the boiler is capable of, it will start to short cycle. This will knock efficiency right down as well as increasing wear & tear on the boiler.

Unless the boiler is located in a garage or loft, it would be better to turn it off at the mains - If the meter says gas is still being consumed, then the meter may be faulty (almost flat battery ?).

@FreeBear thanks. I'll turn the boiler off tonight & try it. See what happens.

Regards the turning off of rads - when I have the fire on I turn off the living room & kitchen completely. Kitchen can stay cool but we're not in & out but the living room can get scorchio as you'd expect.
I leave upstairs as they are.
So your comment about turning them off - is that an issue in the scenario I just mentioned? Just that with a fire being on the rads don't need to be on as well as (is my view on it).

Boiler is located in the spare bedroom.

FreeBear

B0bbyEwing said: So your comment about turning them off - is that an issue in the scenario I just mentioned? Just that with a fire being on the rads don't need to be on as well as (is my view on it).

Boiler is located in the spare bedroom.

Knocking efficiency down due to short cycling is really dependent on how often your boiler fires up each hour. Some boilers, you can set a parameter that extends the time between each burn. Not sure if the WB has that option (my Viessmann doesn't).

Having the boiler in the spare room is good - You shouldn't need frost protection. Boilers will waste some 6% of the heat through the casing, so at least you are putting this energy to some use. One of the reasons I had my boiler installed in the hallway.