Most efficient boiler settings

FaceHead

It would be interesting for Octopus to clarify how you can get 20% savings, without Tim's suggestions of 'Off'. 

Other things that could have this sort of impact might be having a thermostat or timer - I expect this is what they've got to be talking about, i.e. having the heating off during the day when you're at work!

The idea that a 10-20% saving can be gotten from just twiddling the flow temperatures on the boiler - without having them so low that you're freezing - is ridiculous.

Bendy_House

blagoslovljena said:

That’s really helpful guys, thank you. 😊

It is a combi (no hot water tank) with no remote thermostat anywhere and just the TRVs to control the temperature in the rooms. There’s two dials on the boiler with literally just a 1-6 and ‘max’ on each, to control the CH and HW. 

There’s a programmable analogue-style clock - all very old school! But we don’t use the timer function for it as the CH is literally on all the time at this time of year and we’re using all the rooms in the house (small house, lots of people). When it warms up a bit weather-wise I manually turn the CH on in the morning and off when I go to bed, as if I set the timer the noise of the radiators heating up before we get up wakes my kids. 🙄

TRVs are usually on 2 in each room, unless the temperature drops, when I might turn it up a bit in the lounge and bedrooms. I have baby monitors in two of the bedrooms and they usually show room temp as 21-22 degrees, but I can’t really have it lower as I have young kids at home all day.

I tried turning the CH dial on the boiler from 4 to 3 last night, and the HW dial from the ‘e’ setting (whatever that means - it’s where the 5 should be!) to 4, and so far I haven’t noticed any difference, so I think I’ll see how things go today and possibly turn them down again. There’s no digital display or anything to indicate actual temperature on the boiler, so I’m largely just winging it! 🤣

Not having a wall-mounted thermostat is usually a big 'ouch!', and also means your system wouldn't conform with the more recent regs. (Tho' you don't have to conform retrospectively.)

Not having a wall 'stat controlling the overall boiler operation means your boiler doesn't have what they call an 'interlock' - I know, daft name. What it's meant to do, tho', is to turn your boiler fully off for the periods where it just isn't needed, which would be when your house has actually reached the temp required, and a wall 'stat tells the boiler that the required room temp had been reached. At the moment, the boiler tries to keep running all of the time, and it's only when it cannot actually 'shift' the hot water being produced (because most of the rads will have shut down via their TRVs) that the boiler will temporarily turn off its burner, whilst keeping the pump running. The boiler will then be doing what's called 'cycling' - ie it's 'running' all of the time, but the burner goes (cycles) on and off repeatedly to meet demand.

That's not good - more wear to parts, boiler always trying to run, and if you don't have at least one radiator without a TRV, the boiler might be trying to force water around a circuit that's effectively been shut off by its TRVs. Far better is if the boiler fully shuts down when a room stat says "Have a break, have a whatsit - things are warm enough in here. I'll let you know when you are needed again".

However, I would say that in your personal situation, where you are at home all the time, and heating is required all the time, it might not be such a big deal. But, you'd almost certainly save energy if you had a Programmable Thermostat fitted to the wall of the main living area. With this you'd set the temps you want for the times you want them. Automatically off/down overnight, and then back on in the morning after the kiddies' wake-up time!

The 'e' on your DHW stands for 'eco', and it probably the setting that WB recommends. Not sure if that includes a 'pre-heat' setting? Pre-heat will keep the boiler 'hot' by coming on every now and then, and this means you have faster hot water out your taps. But, of course, this also uses more gas. Again, in your personal circumstances where the CH is on pretty much all of the time - and the boiler's fabric therefore 'hot' - I'd say that 'pre-heat' is just not needed. Turning the DHW down that notch probably will give you some savings - the delivered hot water won't be quite as hot.

If turning the CH control down one notch didn't make any noticeable difference, then that's good. I'd leave it there - if not even try one more notch down, at least when the weather become a bit more mild...

TRVs on '2' usually means a room temp of around 18oC, but TRVs are crude devices, so this can vary. Certainly the bedroom temps are higher than a '2' would suggest!

Soooo, do you have at least one radiator in your house which does NOT have a TRV (say a bathroom towel rail)?

Worth also downloading the manual for your boiler and see what output settings they recommend.

Your call, but not having a room stat is not at all ideal. Do you have someone who could competently DIY an install? You can get wireless versions, so don't even have to run cables to your main living room. And you can also get 'Smart' versions for as little as £30-odd, which you can control from a phone App.

blagoslovljena

Bendy_House said:

Worth also downloading the manual for your boiler and see what output settings they recommend.

Your call, but not having a room stat is not at all ideal. Do you have someone who could competently DIY an install? You can get wireless versions, so don't even have to run cables to your main living room. And you can also get 'Smart' versions for as little as £30-odd, which you can control from a phone App.

 Thanks for all your advice!

Unfortunately we don’t have a radiator without a TRV, and I think the lack of a wall thermostat linked to the boiler is due to the fact that the boiler was swapped out whilst we were living in alternative accommodation after the Gloucestershire floods of 2007, so I wasn’t dealing with the process myself. The builder doing my flood repairs arranged a company to do it for us, and they weren’t that great tbh. I thought the wall thermostats came as standard, but they didn’t bother fitting one, and when we subsequently had boiler issues the company that installed it was nowhere to be seen. Been having BG homecare ever since and I’m glad I have, as it breaks down pretty much annually and has done for donkey’s years, which isn’t helpful with kids in the house. 😔

Anyhoo, I did try and look at the manual for advice on the settings, but it didn’t say anything at all, which is why I came to you lovely MSE people for help. 😁

Unfortunately, my husband’s DIY skills leave a lot to be desired, and I’m not much better (unless it’s an IKEA flatpack - which this blatantly isn’t! 🤣), but I’ll look into the thermostat idea. I’d always assumed they were expensive, so it’s quite a surprise to me that they’re not.

Thanks again for your help. It’s been brilliant to have so many folks willing to patiently explain how my heating system actually works - something I’d not really thought much about until the reality hit that my monthly bills are going to go up massively. 😱

Bendy_House

blagoslovljena said:

  Thanks for all your advice!

Unfortunately we don’t have a radiator without a TRV, and I think the lack of a wall thermostat linked to the boiler is due to the fact that the boiler was swapped out whilst we were living in alternative accommodation after the Gloucestershire floods of 2007, so I wasn’t dealing with the process myself. The builder doing my flood repairs arranged a company to do it for us, and they weren’t that great tbh. I thought the wall thermostats came as standard, but they didn’t bother fitting one, and when we subsequently had boiler issues the company that installed it was nowhere to be seen. Been having BG homecare ever since and I’m glad I have, as it breaks down pretty much annually and has done for donkey’s years, which isn’t helpful with kids in the house. 😔

Anyhoo, I did try and look at the manual for advice on the settings, but it didn’t say anything at all, which is why I came to you lovely MSE people for help. 😁

Unfortunately, my husband’s DIY skills leave a lot to be desired, and I’m not much better (unless it’s an IKEA flatpack - which this blatantly isn’t! 🤣), but I’ll look into the thermostat idea. I’d always assumed they were expensive, so it’s quite a surprise to me that they’re not.

Thanks again for your help. It’s been brilliant to have so many folks willing to patiently explain how my heating system actually works - something I’d not really thought much about until the reality hit that my monthly bills are going to go up massively. 😱

Wow, you've been through t'mill.

I'm pretty sure - tho' not at all certain - that an 'interlock' would have been a requirement back in 2007. In any event, your builder does sound a bit pants...

Prog Stats are not expensive, tho' some are fairly so - Hives and Nests, for example, are £100+. The biggest issue is the installation. Again, tho' a wireless type makes this pretty painless.

I have just fitted a second Hive in a local village hall (it has two boilers...), and prior to that they had a manual room stat and just changed the temp using TRVs. For the very first time in the 5+ years that building has been in place, that gigantic Greenstar 440 did something amazing - it turned off.

BUFF

As already pointed out by others I would suggest that a programmable roomstat (one that allows at least to be able to set a different, lower temp overnight whilst you are all tucked up in bed & higher during the day when you are up & about the house)  would be a good idea for various reasons & should, at the very least, pay for itself over it's life.
When I last changed my boiler 13 years ago I reckon that 1/2 the energy savings came from adding a roomstat & 1/2 came from going from an old non-condensing boiler to a condensing.

£300 should be enough to allow for the purchase & professional installation of such a device - possibly much less depending upon what device you decide on.

On the other hand, your existing boiler may be approaching the end of it's life & any replacement will be required to have a roomstat to meet current installation standards so you may wish to just wait until then.


p.s. the 30Si should have an automatic internal bypass so doesn't require 1 radiator not to have a TRV.

BUFF

FaceHead said:

The idea that a 10-20% saving can be gotten from just twiddling the flow temperatures on the boiler - without having them so low that you're freezing - is ridiculous.

More likely 5-8% depending upon installation.
However, combined with load & weather compensating controls it could be much higher.

Bendy_House

Thanks BUFF x 2.

Norman_Castle

blagoslovljena said:

And is it better to have the TRVs on max but the boiler CH set lower rather than the other way round then?

No. A TRV valve prevents a room from being overheated.

getmore4less

Could invest in programmable TRV system.

Then you can have each room at the right temp when in use then off the rest of the time.

Bendy_House

getmore4less said:

Could invest in programmable TRV system.

Then you can have each room at the right temp when in use then off the rest of the time.

That's probably the ultimate solution. Two problems, tho' - one is the high initial cost, and the other is it would still lack an interlock; the boiler would still be running all of the time, until manually turned off.

Of course, Prog TRVs can be fitted as part of an overall control system which includes a Prog Stat, but this is surely many £100's?