Central Heating system?

Question

I am installing a central heating system with a combi boiler using the PEX speed fit tubing. Does anybody know what diameter pipe is needed to supply the radiators? I am after the size of tube from the boiler and also the branches off to the radiators. Cheers

Answer 1

22 mm main circuit with 15 mm branches, with the last two radiators on the main circuit the circuit its self can also be in 15mm.

Answer 2

3/4 main, 1/2" branches

make sure you use oxygen barrier

   Check the psi's on the system tank before testing.    

Answer 3

If all else fails,read the instructions.

Answer 4

This is depends a lot of factors , the main two being the size of the rads and the distance the boiler is from the furtherest rad , I will take it that because you are using a combi , you have no more than two bathrooms , if so and you live in a flat or small house , then 22mm from the boiler branching to 15 mm to the rads will be ok . In a bigger house I would go with 22mm upstairs , and a separate 22mm circuit for downstairs , each controlled by a motorized valve via  a rooms stat and timer , make sure to insulate all pipe work ant test fully before replacing floors ect  

Answer 5

if I said 3/4inch would you accept this as so, if you say yes then you need to hand this job to some one who knows what they are doing,as you certainly do not know, as you would not ask the question