Extending - microbore heating system

[issyg]

Hope someone can advise whether I need to replace my microbore pipes as i am getting different opinions, and costs from builders.

I have a house with the main runs in 22mm pipe and the tails to the rads in microbore. I plan to build an extension which would have normal pipe sizes in it.

Is there any reason why i should have the microbore pipework changed when the extension is built?

Some of the rads will need to be replaced as they have leaked a bit in the past, and I'm concerned that if the system is flushed there might be some more of that happening.

One builder is telling me i need to change the mocrobore and the other is telling me it isn't a problem. I am a layperson so have no idea who is correct or if they both are!

Thanks

 

[Charnwood]

I am a layperson so have no idea who is correct or if they both are!

The problem is they are builders.

Thankfully you've come to the Plumbing and Heating forum and not the Building forum.

I'm no expert, but one will be along shortly to help.

 

[doitall]

If the tube etc is in good condition then no need to change it.

Any new rads will need to go back to the manifold or main heating flow and return.

 

[Agile]

You have not said what size it is.

10 mm is little problem!

8 mm is quite small, does not permit very high flow rates and is easily blocked.

A condensing boiler is going to work better if it has to be on microbore as it expects a higher temp differential across the rads.

Mixing 15 mm and microbore will mean it needs careful balancing.

Yet again I would always recommend a heating engineer rather than a builder!

Tony

 

[issyg]

The microbore is 8mm and has been in use for 27 years. I only hought the house a few months ago so I'm not really sure how well the system works, although it seemed generally warm enough in the house. Im in a very hard water area so I am concerned about rads and pipes getting sludged and blocked up.

The plan is to replace the boiler when the extension is built. Replacing the microbore is not straightforward, involves major disruption and cost. But i do want a heating system that is trouble-free and effective.

 

[doitall]

You sure it's 8mm at that age ?? I would have expected 10mm.

Easy to blast each pipe out with a hose or pressure jet, does need doing individually though.