Replacing microbore - help please

[Freid]

We've just bought a new house, and I'm looking to replace the existing radiators which are very old, not that efficient in terms of size/heat, and not in the ideal locations.

Carpets are being replaced, so coming up shortly, and rewire happening in the next week or so, so perfect opportunity to deal the radiators.

I've established that there is a short length (5m or so) of 22mm Flow and Return from the boiler, which is then reduced to 5x 8mm microbore at a manifold (pic below). The 8mm then runs to each of the rooms radiators.

May as well take the chance to replace the microbore, but just wondering what the best thing to do at the manifold is? I've moved/ replaced lots of radiators in my last property, but it already had 22mm stepping down to 15mm tees at each radiator, rather than this sudden reduction from 22 to 8mm all in one location. I've put a wee plan below to show where the 22mm runs too, and where the existing radiators are. The 8mm basically just works it way into the landing before splitting off/returning to/from each room.

Leaning towards using JG Speedfit as been v happy with it in the past.

Any advice welcome!

 

[Notch7]

Leaning towards using JG Speedfit as been v happy with it in the past

I believe plastic can cause problems in hearings systems…maybe it’s not an issue with the barrier pipe that’s sold these days….hopefully a pro will advise.

Don’t forget push fit 15mm doesn’t have very big bore size inside the inserts, so it’s not like swapping 10mm microbore copper for 15mm copper

I believe the rule of thumb is 3 radiators off one 15mm run…..but not sure how easy it is changing from a manifold microbore layout

Is there a separate circuit for downstairs?

 

[Madrab]

The issue with plastic is when using say 10mm as the inserts are narrower again and can restrict the flow a little especially on larger systems so not advised.

Extend the 22mm out to the centre of the space in the hall, branching out in 15mm to bed 3/2/1 as you go and then end of the 22mm in hall reduced out to bed 4 in 15mm. Try to make the runs of 15mm similar lengths.

Obviously copper is better but if DIY'ing then 15mm plastic should do the job fine. Just make sure everything is flushed initially, well inhibited and kept clean over it's lifespan and you shouldn't have an issue. Run the plastic with minimal no. of fittings to underneath the rad valve then elbow up in copper to the valve. As suggested ensure it's barrier pipe but any of the speedfit that would be supplied should be.

 

[Freid]

The issue with plastic is when using say 10mm as the inserts are narrower again and can restrict the flow a little especially on larger systems so not advised.

Extend the 22mm out to the centre of the space in the hall, branching out in 15mm to bed 3/2/1 as you go and then end of the 22mm in hall reduced out to bed 4 in 15mm. Try to make the runs of 15mm similar lengths.

Obviously copper is better but if DIY'ing then 15mm plastic should do the job fine. Just make sure everything is flushed initially, well inhibited and kept clean over it's lifespan and you shouldn't have an issue. Run the plastic with minimal no. of fittings to underneath the rad valve then elbow up in copper to the valve. As suggested ensure it's barrier pipe but any of the speedfit that would be supplied should be.

Thank you, that makes perfect sense and was in line with what I was thinking, so nice to have it confirmed.

Once I’ve got all the carpet up and easy access to all floorboards I’ll assess whether we go copper or speedfit depending on space etc.

Many thanks!