Rad balancing Idea

Maxx470 · 5 Jan 2011

Please don't shoot me down here but, I'm probably wrong but would like to hear your expert opinions.

I want to balance my central heating system because we have moved and added rads etc.

I have read the guide to doing it in the forums faq's and will use this method if my idea is rubbish.
Instead of opening up all the control vales and the LSV's is it possible to open up all the control valves and Close the LSV's, start up the boiler and then go around the rads and slowly open the LSV's just until the temp difference is 10 - 12 c difference ?.

I thought that if the desired result was this difference then why not use this method as it would seem less running around etc ?.

I look forward to the replies.

Hugh Jaleak · 5 Jan 2011

You'll probably find that method gives you more running around.

Water is lazy, will take the easiest path. So, it will flow through the nearest rads first, those further way from the start of the system will be starved. By closing down these first rads you start to force the water to the further points.

Maxx470 · 5 Jan 2011

So it is possible then is it ?.
On my system the boiler is at the end of the house in a utility room and the 22mm pipes run from it to roughly the middle of the house into a manifold and from there all the rad are fed, so it's hard to find the nearest rad etc. We then have the 2 upstairs rads which appear to feed from near the zone valve/pump etc which is in an airing cupboard, again roughly iin the middle of the house.

Another question, would a poorly balanced system cost a lot more to run in fuel ?, I have a feeling most of the LSV's are pretty wide open.

D_Hailsham · 6 Jan 2011

Read How to balance a CH system

bengasman · 6 Jan 2011

The method described on the forum is generally the best way of doing it, if your method was better, we would have posted that one.

D_Hailsham · 6 Jan 2011

bengasman said:
The method described on the forum is generally the best way of doing it, if your method was better, we would have posted that one.

The method I gave the link to is based on that recommended by Drayton. See TRV Commissioning Guide. However it departs from Drayton's method by saying that TRV heads should be removed. This is consistent with the advice given by other commissioning engineers. See, for example, page 17 of Balancing of Radiator Systems by Tour and Andersson. (The whole book is worth reading.)

Agile · 6 Jan 2011

The OP's idea does not work because the pump pressure reduces as further rads are opened and that will reduce the flow in the first opened rads.

If he is lazy then my simple setup up will usually work well enough. But not a proper full balance.

Close all LSVs then open 1/2 turn near boiler, one turn for most and 1 1/2 turns for furthest ones.

Tony

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Rad balancing Idea

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