Mixing CH Pipe Sizes

[Stuart]

I'm replacing one CH radiator .The system is 10mm copper with adaptors where the pipe enters the valves .. I need to alter a small length of pipe connecting the rad as the rad is a little larger than the old one . To make things look neater ( and to avoid buying a coil of 10mm) is it OK to use 15mm between the valves and just under the floor with reducers to join up to the 10mm ... Will this cause any problems .? Stuart

[Ian Stirling]

There may be minor issues with slightly increased sludge buildup, at the changes, but in practice, you'll see problems everywhere when this happens. (if the system is not adequately protected)

[Stuart]

Thx Ian ...

The system doesn't allow for any sort of additive ,It's a single feed Primatic and there is no way of adding anything . When I removed the old rad I was surprised when I emptied it and flushed it out as to how little "black stuff" there was came out of it .

Stuart

[Lobster]

There's always a way....! See:

[<me9]

anyway, as it is so easy to lose the bubble separating primary and secondary circulation. A new (indirect) cylinder and a sealed primary would solve the problem.