Angela

I couldn't find the clip on thermometers anywhere, so I bought the digital
thermometer recommended here from CPC (part number IN0229366) at £30
(http://tinyurl.com/s9aq) and followed the advice on balancing at the FAQ ..
http://www.diyfaq.org.uk/plumbing/pl...html#balancing

Firstly I found huge variations in temperature across the radiators, some
were 2-3 degrees (indicating very fast water flow) and some 25 degrees. The
boiler pipes showed a 20 degree drop until I switched the (Grundfos 15/50)
pump to it's maximum speed.

I could get readings easily from the radiator pipes as they were all
painted, but the brass/copper fittings of the boiler in/outs made it hard to
get a stable reading (the non contact thermometer doesn't like shiny
surfaces). I sprayed a blob of matt black paint onto the pipes and solved
that problem.

I went around the house carefully setting everything, and as indicated in
the FAQ, nothing really happens to the flow rates until the valve is wound
down less than half. My valves had two and a quarter turns lock to lock and
I found the radiators that had the lowest drops needed to be wound to about
1/3 or 1/2 turn from closed to have any effect.

Once the 3-4 radiators with low drops were restricted down, the other slow
radiators started coming closer to the 11 degree drop. As the valves were
getting close to their final settings, I found the boiler drop was down to
6-7 degrees and I could set the pump back to "2".

Finally I found some other useful comments on the www.eco-hometec.co.uk site
here http://tinyurl.com/k0rx The comments here about the operation of the
thermostatic valves has made me think about replacing my pump with the
Grundfos Alpha + which electronically modifies the flow to suit demand as
the thermostatic valves open and close. A few of my rooms are in irregular
use, so I tend to leave them on minimum, this causes other valves (bedroom
particularly) to whistle a little as they modulate the temperature. It might
be the new pump could supply a lower pressure in this case (talking myself
into another DIY task).

The only hassle I found was the house getting up to temperature (even with
25 on the stat!) or the boiler taking thermal rests after a couple of hours
of running. You need to make sure the boiler has been supplying hot water to
the rads for at least 5-10 mins before you take a reading. The digital
thermometer was a much better way than waiting for clip on stats to
stabilise.

Good luck. It looked a bag of worms when I started but to run round the
house and see 10/12 degrees across all the rads and boiler was a job well
done. Thanks to the group and faq for help.

Colin

PS Tiny URL was broken by the time I finished typing this, the Grundfos pump
info is he
http://www.grundfos.com/web/homeUK.n...ag/DMAR-4QHJ4E