radiators don't get hot in winter

[caz26]

Dear All,

I'm guessing the boiler isn't up to scratch but would appreciate some explanation into why when its just cold outside our radiators do get hot, but soon as it's baltic outside (and inside) the radiators barely get warm (not hot to touch).

Our boiler is a worcester highflow 4.5 22.9kw number. I appreciate this likely aint enough for a detached stone built five bedroom house, but that aside I'd like to know if upping the spec of the boiler would in itself lead to hot radiators.

Radiators are bled, not full of sludge and two of them were replaced last year with new but they don't get to temperature either.

Any advice welcome
Stephen

 

[jackthom]

To find out if the boiler is the problem you should feel the CH feed pipe close to the boiler to see if the water coming out of it is as hot as you would like

(I'm assuming there isn't a temperature readout display on the front of the boiler which would make it easier to see what was happening)

If the boiler has been running flat out non-stop for say half an hour, and the water coming out of it isn't hot enough, it must be struggling with the size of the system.

On the other hand if the boiler is occasionally producing very hot water but in short bursts (cycling) there is a problem with the flow through the radiators.

 

[caz26]

Thanks for that reply. I'm guessing (as I thought) that the boiler isn't up to scratch for the job but can you explain why rads are hot when it's mild, but not when cold?

Any value in a second hand boiler-excellent water flow!

 

[jackthom]

Just for example if you are aiming to heat the house to 20C.

When the temp outside is 0C the system will require twice the amount of heat from the boiler that it would on a milder day of around 10C. When it's Baltic inside the cold air will very effectively cool the radiators more efficiently.


As I say, on a cold day make sure the boiler stays on firing constantly and is not having an occasional sneak rest. Then you'll know its doing it's absolute best and is just not up to the job.

It would be a disaster to pay for a new one and find out it was something else causing the problem.