How to determine radiator order for balancing?

[jntelfer]

Hi all, we've just had a new WB Greenstar 34 CDi fitted to replace our 20ish year old Worcester 240, and very pleased with it we are.

However, the radiators in the house have never been balanced and various rads have been added in a patchwork way over the years (two bay rads, two in a loft extension, various replacements).

I've been following the balancing guide on this site, but we have a problem, there's little sanity in the order they seem to receive heat. Some upstairs get hot at the same time as others downstairs - even with three of us running around checking them we've not been able to determine the true connection order.

The only other way I can think to do this is open all the lockshields fully and measure the inflow temperature at each rad - assuming that once they settle the ones closest to the boiler will be hotter. Is this a reasonable starting point before balancing?

 

[D_Hailsham]

I wouldn't be too bothered about getting the order correct; it just makes life a little easier, that's all.

I assume you are using thermometers to measure the flow and return temps. The flow temp will not change very much from one rad to the next, so you need to concentrate on the return temp.

Start by setting all lockshield valves to a quarter turn open. Leave them for 15 minutes to settle down, then measure the return temperatures and compare to the required drop (10C or 20C). If the drop is too small, close the LS valve by a 1/12th of a turn; if too large, open the LS valve by a 1/12 turn and check again -leaving time for the temperatures to settle down.

Repeat until you are satisfied, but don't expect to get it 100% right.

If your system has a separate pump, you may find that you can reduce the pump speed. This will be necessary if you can't get a large enough drop across any rad

As for your question about the TRVs on the 'wrong' side, you still adjust the LS valve as above. The reason you can get noise is that the pressure across the valve is too high, which is normally due to incorrect balancing. If you balance as above you should not get this problem.

 

[jntelfer]

That's good to know, thanks. I'll have a crack at it tomorrow.