New combi boiler, and the house is not heating up properly - bigger radiators needed?

[twodoctors]

Hi all,

I posted about changing two leaky radiators and valve recently. Going to have a go tomorrow...

The problem I'm noticing a bit more, as the weather gets a bit cold, is that the is not really heating up well at all. I'm not entirely convinced it's a radiator balancing issue. All radiators do get warm, and I'll have a proper go at balancing all of them after doing the work. However, it's taking an age to get up to even 18C. I have tried setting the flow temp to 60C (like they said on recent advertisements about saving energy) but the house is cold. Tried turning it up to 65C and then now 70C and I think it is making some difference.

I just had a trawl through this site, and someone mention a 1 pipe system... I think I have a 1 pipe running through a 5 bedroom house with 12 radiators. I was never asked about changing to a 2-pipe system. Then I saw something on YouTube, someone mentioned in passing about condensing boiler running lower flow temp and therefore needing bigger radiators to generate the same heat and make things efficient. Is that what I'm looking at now? Is getting new radiators the answer to my cold house problem?

Thanks all.

Adrian

 

[cross thread]

If you system is “ old “ the rads may have been sized for a flow temperature of 75 degrees ,so if t to run at a lower temperature is going to need bigger rads.
some online calculators to see what heat a room needs and you could look up the size of your existing rads to see if they are the right output.

 

[twodoctors]

It is older. The house was built in 1990 (younger than me). The radiators are all of the older hexagonal shape ones (if you know what I mean). Some of them has a radiator cover on them as well... Which wasn't noted to be a problem before we fitted the new combi.

I'll see how I get on with the job tomorrow. I will probably have to change a few of them...

 

[elisa123]

Take the radiator covers off. The interrupt the flow of heat.

 

[twodoctors]

Managed to fix my radiators, and kind of balanced the system. Most of the radiators are piping hot so a bit more fine tuning is needed. However the house feels a bit warmer...

...but I don't think it was the radiators. I think it's because I closed all the air vents on the windows. It was 15C yesterday when I was working on the radiators during the day, compared with 12C ish with the vents open. A bit more condensation on one of the windows, so I might have to open one/some vents again.

My question now is: What is the ideal temp to set to when heat is not needed? I was in the old non-condensing boiler mindset and set it to 12C. Read up on the flow temperature and just wondered what this should ideally be at. I've now got it to 15C...