Plumber says boiler too small for flat/radiators

Sponsored Links
My January usage was 210cu.m which is (about) 2343kWh
Looks like that's a bit high.

As a rule of thumb, there about 11.16kWh in a metre of gas (multiply by 11 for "near enough")

Remember the daily standing charge on top.
 
I don’t see how. We pay £100 per month on a standing order and currently we are £253 in credit but we have got the colder months coming!

You paid just £15 for gas heating and hot water for the whole of January? That’s just 50p per day. Were you away on holiday or did you sit covered in blankets and go to bed at 7.00 at night?

None of those things. Its 22C in the living room now, most rooms run at 18 to 20C. Night fallback temperature is set to 14C, but it never falls below 17.5C overnight in the house. It begins with a day temperature a 17C, which I might nudge up a bit higher as the day progresses to 20C. That's temperature in the hall, where I have no TRV.

She does a lot of cooking, in a double gas oven / gas hob. I have the place very well insulated. I pay £62 per month standing order for both E&G combined and had an £83 refund two weeks ago as I had paid too much.

I log my readings for G, E and W into a spreadsheet each Sunday morning, just to keep an eye on things.

I also run a fancy weather station which stores indoor, outdoor temperatures + humidity, wind speed and direction every minute.
 
Last edited:
We have our living room set at 23.5°. Heating is on from 5.30 to 8.00 each morning as wifey gets up at 6.00 then 1.00 to 11.00 at night but if I have a shower after that time I boost it for another hour. Hot water is on constant and we have gas hob but electric oven.
 
Sponsored Links
Three story 6 bedrooms, 14 radiators 18 Kw boiler oil fired and no problems. It may need an extra expansion vessel if the amount of circulated water increases, if not fed from header tank, as to how heat retained in radiators will affect how heating will depend on control, with oil the boiler is simply switched off/on so if the thermostat is in the room with the cast iron radiators it could increase the hysteresis in the other rooms. With a modulating boiler then it should not really affect the hysteresis as long as any thermostat modulates boiler and does not simply switch off/on.

My sons first house he claimed the boiler was too small and it took ages to heat house from cold, on investigation it was found the lock shield valves had been left wide open, so instead of heating all rooms together, it heated one room until TRV worked and then the next until that TRV worked and boiler was running on minimum output because return water was too hot.

With a modulating boiler there is more of a problem being too big to too small, a boiler may give 6 kW to 24 kW or 10 kW to 30 kW and it is the minimum being 6 kW or 10 kW which has more effect that the max output, as with 10 kW boiler will cycle more so more of a hysteresis that the 6 kW.

I note location of my thermostat means my 18 kW boiler does over shoot the mark by around 1°C even with a Nest thermostat, it is between 4 radiators, hall, shower room, kitchen and living room and what doors are open or closed makes a huge difference to the hysteresis so Nest can't work out how much the over shoot will be as is varies.
 
9 rads and it has never been balanced in 35 years, it has just never seemed to need it. Prior to my installing TRV4's, all the rads would get hot, though some rooms would overheat and I would turn the valves down a bit in those to reduce the flow. Since fitting TRV4's 18 months ago, I have still not felt the need to balance them, though over time and use, I have tweaked the TRV's to set each room's temperature.

The place was originally built with steel window frames, open fires in living room, bedroom and a coal range in the kitchen. Replaced by wood frames, gas fires and cookers prior to my moving in. It was always freezing cold and draughty in winter, improved in the mid 80's at the expense of high gas bills, with central heating.

Over the years I have rectified all of those inefficiencies, both electric and gas - I now consider my bills to be very acceptable.
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Back
Top