Extending Micro Bore system without using manifold


8 May 2007
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United Kingdom
I wish to add 2 radiators (in an extension)to our Combi powered micro bore central heating system , but to save a lot of work getting access to the manifoilds (under floor in main part of house)and running excess pipework can I tap a 15mm pipe (and then branch to 10mm to the 2 rads)from the 22mm flow and return pipes near the boiler to provide for this.
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Thanks Craig, I guess that as long as the system is fully balanced then you can mix manifold sytems with 'traditional' system design?.
The principle of the microbore manifold is to ensure easy balancing. You may find that, by connecting into the main f&r near the boiler it will cause problems in trying to re-balance the existing circuits served by the manifold. The balancing valves on the new radiators may have to be shut down so much that you may get noise problems through these rads.
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Thanks Giblets, I understand what you are indicating. What I'm trying to avoid is running 40ft of 10mm pipe from the current manifold which is way over on the opposite side of the house from the boiler when the extension is right next to the boiler. I'm hoping to reduce the pipe length to 20 ft of 15/10mm pipe by avoiding the manifold and going a more direct route from the 22mm Feed/Return pipes near the boiler.
Any further thoughts from anyone...I'm getting close to starting work. Thanks

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