Replacing microbore system

[rstark]

Hi

I have just brought a chalet bungalow that has microbore with 10mm (of imperial equvalent) throughout downstairs, I want to modernise the system and fit the radiators with Thermostatic Valves, a couple of queries.

1) My simple plan is to remove the manifold and run a pair of 15mm pipes (in plastic) in a circuit servicing the downstairs rads (7 in all) with perhaps the need for a bypass valve at the start of the circuit.

2) The old radiators are all double entry, can I reuse them. One end is blanked off with a square key, I assume I can remove and fit a pair of locknut and TRV valves? If possible is this advisable? would I be better getting newer radiators in terms of efficiency? the old ones are quite sizeable compared with more modern installations, but if I can reuse I would save a good few pounds.

Does this sound like common sense approach? I am not a plumber as you can tell but like to try these things (the house is empty and I am gutting it so now is the ideal time to do this work!)

Cheers
Rob

 

[flameport]

If the radiators are old, dispose of them - regardless of whether they can be reconnected to the new pipes.
They will be rusted up inside, and will be the source of problems for years to come.

Saving money is all very well, but when one of the old radiators leaks disgusting black water all over your lounge, you will regret not replacing them with new. Or the boiler / pump / whatever fails due to gunge and corrosion in the system.

 

[Nige F]

Get a new combi boiler too while you`re at it sod the expense , and use copper pipes not plastic . If it was one of mine - which it aint cus I didn`t do microbore - it would still be pristine cuz I cleaned and fernox`ed all my installs - there`s a lot of good systems in E. Sussex down to me

 

[Agile]

Microbore works because all the circuits are a single spur or radial circuit from the manifold.

You can replace each individual circuit in 15 mm if you wish but what I think you were proposing might not work!

The rads can be used if you fit a valve at each end and connect to a 15 mm circuit. How dirty they might be would need to be assessed. However the effect of dirt will be far less with 15 mm pipework than 10 mm!

10 mm microbore works quite well. Its 8 mm that is problematic because its so small its easily blocked.

TRVs would be a useful energy saving addition and might save 5-10% if used sensibly.

Tony

 

[Whitespirit66]

Running 15mm as a distribution circuit to service the rads is all well and good if you only have small rads. 15mm can only distribute 15,000 BTUs successfully. For eg. a 600mm X 1000mm double rad can be the best part of 5000BTU, so you can quickly run out of capacity.

To work out the total BTUs for your rads, measure them, and look at Screwfix or similar website/cataloge to get approx outputs for each of your rads. If, as I suspect, you exceed the limit for 15mm, you need to run the main distribution circuit in 22mm, teeing off in 15mm to each rad.

I would run 22mm anyway. Better safe than sorry.

 

[Agile]

You and I would distribute in 22 mm to the upstairs and downstairs in a three bed semi.

But its surprising how many would run in 22 mm until out of sight under the floor.

Tony