Radiators fed by microbore not getting very warm

[Ian Simson]

Hi all, I suspect I already know the answer to this, however someone might be able to offer some words of wisdom.

I bought a 2 bedroom bungalow in the summer however now that its winter and the temperature has dropped that I have realised how poor the heat output from the radiators fed by microbore pipes is, this is even after having the system power flushed (which i will admit did remove an awful lot of dirt) The flush certainly made a difference however the performance is nowhere near as good as my previous house. There are two radiators on the system that are fed via 15mm copper and these work just fine, as well as the hot water therefore i do not think there is anything wrong with the boiler, pump or valves etc everything in my mind points towards the microbore manifolds or piping not working efficiently.

Re piping the system is not really an issue as its virtually all supplied under the wooden floor and i have done this kind of work in the past successfully, however I do not want to do this until i have exhausted all other avenues. I have attached a quick drawing i have put together of the system as it is now.

 

[ianmcd]

read in the FAQ about balancing your system

 

[jackthom]

I would first try turning off the 15mm fed radiators then see whether any or all of the microbore ones dramatically improve.
As ianmcd says it may just be a case of balancing so the microbore radiators get their fair share of the flow.

 

[Ian Simson]

Thanks guys I will try that tonight and see what impact it has.

 

[gigz]

Also check the heating thermostat on the boiler is set high enough.