10mm microbore for last metre to radiator?

My CH system is mostly 10 and 12 mm ( dunno why both) apart from the run from the boiler to the hall ( 7-8 metres) which is 22mm .The microbore branches off that . It's been like that for 20 odd years and there has never been a problem

I have 10mm microbore in my present and previous house (combined 13 years) and have not had any problems. I was told the main issue with MB is the potential for clogging up (or so the heating engineer said who serviced my boiler)

I worry about clogging hence my question about whether it stops you flushing effectively.

With microbore I can connect things up much more easily in difficult- to_access palces.

Robert

Being smaller, the flow rate will be higher in the pipe. You won't be able to blast the radiator quite as well. You shouldn't have a system clogging if it's properly maintained.

It will restrict the flow, but unless this is a large radiator which is already flow-limited by a long pipe run, this shouldn't matter. Might need to adjust the flow on it afterwards.

The other thing is it's more fragile than 15mm, and more likely to bend or break when knocked, e.g. with a vacuum cleaner.

Could use 15mm for the piece from rad to just under the floor

i think it's going to be easier for me to chase 8mm or 10mm into the plaster and to tuck it behind the skirting boards without too much ripping apart. I guess the bend radiuss of 8mm is quite small also so I coudl avoid a lot of elbows.

Robert

Sorrym yes, I was originally thinking 10mm, but I have redone the flow calculations using 8mm and it seems OK if I have up to 1.5 metres of

Robert