Central heating pipes

[G1zm0]

Hi ,
Im thinking of.replacing all my old radiators that are nearly 40 year old .
The piping to the rad is 8mm microbore connected to 22mm pipe that is laying g on ground, half of it is insulated.

I want to change this to 15 mm to rads and a new length of 22mm.

Under my floors I can crawl around within the part where the main flow and return is pipe are .

I was thinking of using either all plastic for then 22 or copper with plastic branches to the rads .
Whats the best way to get the branches to to the rads without lifting floor ?
Could I just attach the new pipe to the old pipe and pull it through (making sure hole is big enough at rads?
Could I use the old rad brackets to hang new ones?

 

[cross thread]

Rad brackets will not be the same,you might pull plastic pipe through by attachment to the old pipe but no chance with copper

 

[winston1]

Why do you want to do this? If it ain’t broke don’t fix it.

 

[G1zm0]

Why do you want to do this? If it ain’t broke don’t fix it.

Because my radiators take hours to heat up, its about 1 degree per hr , I've a towel rail plumbed in 15mm and it heats up quick.and my boiler keeps cycling , so a bg engineer has put it down to the small pipe size

 

[JohnD]

have you added a magnetic filter and given it a chemical clean?

 

[winston1]

Because my radiators take hours to heat up, its about 1 degree per hr , I've a towel rail plumbed in 15mm and it heats up quick.and my boiler keeps cycling , so a bg engineer has put it down to the small pipe size

Microbore heating systems were very common yesteryear and they worked. I would think more likely a pump problem. I would get a second opinion before ripping everything out.

 

[G1zm0]

The boiler cycles every 60 seconds , whats the best way to test pump , its a gunfoss? And it does run , I've got a willow one thats in garage brand-new, need to see if its compatible.