Why are my radiators not hot?

I’m not proud about this one and feel rather stupid but I’m going to share it anyway – it may help someone avoid falling foul of the same stupidity that I did.

I’ve seen adverts (by British Gas I think) whereby the elderly lady is getting help to save energy over the phone and she follows the instruction and turns down her boiler. I internalised this and one summers day turned down my boiler. You can see where this is going can’t you?

So the following winter my radiators weren’t hot and I was scratching my head. I checked the hot water cylinder thermostat was working, the 3-way valve, the Nest control hub, the individual thermostatic radiator valves, I bled all the radiators, I balanced the system.

Then, Eureka! I realised that the dial on the front of the boiler wasn’t a simple “use more or less energy for the same result” dial. It is actually, like most other controls in a heating system, driven by temperatures. In this case it tells the boiler how hot to get the water flowing through it.

So, if it’s in a middling setting my radiators will only get to a middling temperature and they won’t heat the house effectively and, therefore, the heating will be on all of the time because it’s never warm enough. By dialing it up to a higher setting, what do you know, the radiators get warmer! The house gets warmer! Not only a bit warmer but it actually gets to a temperature whereby the house is warm enough and the heating turns off!

If I had the time I’m the sort of person who would like to do some experiments and understand what the optimal setting is. Too hot and, no doubt, there will be a point of diminishing returns. Too cold and, as I now know all too well, the house doesn’t warm up and the heating ends up being on all day.

Anyway – lesson learnt. Hope my sharing of my stupidity helps someone else!