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The Natural Philosopher

wrote:

It will be a wet system. So I guess my question is - is there much/
any difference between suppliers of these systems? In fact, is there
a "supplier" per se, given that it's just a system of pipes and mixer
valves.

Well I got all my stuff from Polyplumb. Its as good as any..I DO like
the manifold with the little flow gauges, and the modular installation tho.

I think the whole experience can be summed up with a few salient points.

1/. You can reliably expect no more than 50watts/sq meter. That means
that its not suitable for poorly insulated houses.

2/. Efficiency of the actual 'radiator' - the floor - is critically
dependent on the ratio of the insulation below, to the inadvertent
insulation above. That is, if you want rugs carpets and furniture on a
wooden floor, you had better be prepared for a LOT of insulation
underneath, and pretty hot floor temperatures e.g. under the sofa! Thats
why you need a temperature regulator to prevent the floor getting hot
enough to crack!

3/. The screeded floor represents a HUGE mass. there is at least a three
hour lag to getting anywhere near a 'warm room' and if your output is
marginal, it can take far longer.

4/. If you have an auxiliary pump, you will probably need a relay to
control the boiler.

5/. Because of the time lags, careful thermostat siting, possible
subzoning and a 3 channel controller are almost mandatory. Or one of
those clever predictive thermostats and no timer at all. In deepest
winter running 24x7 seems to result in no more boiler activity than timing.

Having said that, the final result is excellent. We are more comfortable
with warm feet at lower room temperatures than with conventional rads.

Anyway thanks for the help so far.

Ted.