Renovating 3 bed flat with 8/10mm pipes. Worth changing to 15/22mm ?

[Talay]

All radiators need replacing, 3 in bedrooms, 3 in lounge, 1 in kitchen, 1 in entrance, 1 in hallway.

Current setup is 8/10mm pipes and 20+ year old gas boiler.

Is it worth it to feed radiators with 15/22mm and just replace all non 22mm plumbing in the property ?

 

[Madrab]

If it's all coming out then to have the fastest warm up and the easiest system to maintained the standard is a 22mm backbone with 15mm branches/feeds to the rads.

 

[Talay]

If it's all coming out then to have the fastest warm up and the easiest system to maintained the standard is a 22mm backbone with 15mm branches/feeds to the rads.

Thanks.

Forgive the layman's question but any reason why not to have 22mm all round ?

Why branch down to 15mm ?

Is the trade off on performance not important or would it put too much strain on a boiler ?

 

[just pumps]

Check the lease if the flat is leasehold.

 

[winston1]

Thanks.

Forgive the layman's question but any reason why not to have 22mm all round ?

Why branch down to 15mm ?

Is the trade off on performance not important or would it put too much strain on a boiler ?

Pipe sizing is decided on load and flow rate. 15mm is adequate for a radiator and fits available radiator valves.

 

[Talay]

Check the lease if the flat is leasehold.

Freehold owned by management company which is owned by the 12 flat owners with 950 years remaining.

 

[Madrab]

A 22mm backbone centralised for the system and as equal length of 15mm pipe feeding each radiator will ensure a system that heats up uniformly with the minimum of balancing required. It's the optimum setup for a small to medium central heating system, once you go larger and until you get into larger sprawling properties then 28mm and secondary circulators could then be considered.

As suggested it's also the standard rad valve size and hekos to keep the costs down. It also allows for easier drain down and cleaning if required in the future, though if the system is installed and commissioned properly then cleaning shouldn't really be an issue.

 

[picasso]

I changed my way of plumbing flats to prevent leaks under the floor, I now run 15mm pipes from a manifold under the boiler to each rad, uses a bit more pipe but your not digging the floors up in a couple of years trying to find out why the ceiling downstairs has water dripping through it.