hey, can you in theory add larger pipes to a microbore system (8mm)? or will it screw it? have a pressurised 8mm system and a radiator thats too big and/or a damaged pipe. spoke to a few people some said pipe is kinked rad should work, others said rad is too big, and one said adding bigger pipes to the existing system will cause the rest of the radiators in the house to stop working properly - is this the case if so why has nobody else said this!! wish there was a slight consensus as to if this is a bad idea or not. just want a warm home.
around 2.4kw (90% sure) run is maybe 7-10m? not 100% on the route of the pipe as the manifold is at the top of the stairs and rad at bottom. think it runs through the bedroom and down.
should add, inital plan was to come off before the manifold on the 22mm (nearer boiler) and cap off old 8mm pipe. not come off a 8mm pipe and widen to 10 or 15. could this scupper the entire system.
The system may just need balancing but first approach is to turn off all the working radiators and see if the luke warm heats up any better . you need a heating repair technician to visit and work out the problem,its very to diagnoise circulation faults. Some onsite tests can be carried out,these will be bespoke to your installation .
I'd check your central heating pump is working properly. They can be the cause of untold problems if they're on their way out or simply sludged up. Bear in mind your radiator is effectively a series of big, open pipes. It doesn't really care much if the pipes feeding it are big or small.
And ignore what people are telling you about replacing 8mm to 15mm ruining rest of system. It won’t if the new pipes to rad are carefully balanced by closing the lockshield rad valve down
I ran some calculations. Drawing 2.4kW at 20* dT gives a water velocity of 0.8m/s in 8mm and a pressure loss of 80mBar over each 10m leg. 10mm pipe will halve the pressure loss and 15mm will reduce it to 5mBar.