Microbore Balancing Query

[thirl1804]

Hello

I need some advice regarding my central heating pump and a balancing issue I have.

My house was built in 1999 and has a microbore central heating system throughout. Recently, I removed a radiator to paint behind it, when doing this I cracked one of the joints and it began to slowly leak. To fix this I drained the system and patched up the leak OK.

However, since this I have had a problem with balancing the system. I believe these microbore systems use manifolds rather than daisy chaining the rads so I’m looking for general information regarding this.

The problem is that I have to have my CH pump on its highest setting to get any water downstairs. Anything other than the highest setting results in just the upstairs rads getting hot water.

I have two queries which I’d appreciate comments on. Is it bad to constantly run your CH pump on its highest setting? There is a fair amount of vibration and noise from the pump.

My second request is can anyone point me to any documentation/links to explain how these manifolds are normally situated in a house as this may give me some idea of how to balance the system better.

Thanks in advance for any comments regarding this.

 

[Bahco]

FAQ no 8 will help your balancing but I know that microbore is more difficult to balance.

 

[Doctor Drivel]

If only a pipe has been fixed, then the system should remain balanced when re-filled. Sounds like air somewhere.

 

[Agile]

To a large degree microbore is self balancing as a result of the high flow resistance of the pipe.

If the manifold was central and all the pipes were the same length length then the flow through each would be about the same.

The only reason why plumbers find microbore difficult to balance is because all the adjustment is in the last turn on the rad valve. Many plumbers are pretty rough and think a fine adjustment is 2-3 full turns!

With microbore a starting point could be all valves only open 3/4 of a turn and then make movements of just 10 degrees at a time!

Tony