On 23 Feb 2006 12:11:52 -0800, "Ross"
wrote:

Yes the rads are hot so boiler would seem ok. I only have one
thermostat and that is in the hall. When it is mild, this clicks off
when 20c/21c is reached. When it's cold it never clicks off as it never
gets up to temperature. On the old boiler, I remember when elderly
aunts used to be expected, we used to click it up to 23c and it reached
that temperature. Mind you, it was very warm!


have a look at the original point and Ed's comment - i.e. are the
radiators hot all over and is the return water temperature cool?
This would be circulation issue. THe only other is if the boiler
burn rate is set low as mentioned earlier. The fitter should be able
to test that.



I've tested thermometer readings in each room - most are 18c, one is
20c. So it looks like draft proofing, but I come back to my original
question, how can I get this tested?


It's possible to work in two ways.

1) Calculate the heat loss. Measurements, materials and temperature
drop. This is reasonably good. What you can't do is to reliably
measure the heat required to heat the air replacing what's there - in
other words, what is lost through draughts. There are typical
estimates for that and these are taken into account when sizing a
heating system - or should be. You could get a heating engineer
to do this work for you but I am not sure that it leads anywhere.

2) If the heating were working properly and you know the temperature
of the radiator on flow and return side, you can look up the output on
a manufacturer's data sheet.


If 1) 2) then you have a problem that heat loss is greater than
supply.

Two solutions to that:

a) Increase heat

b) Reduce heat loss


Draughts and loft insulation are probably the two first places to
start. Cavity insulation and finally double glazing would follow in
terms of return on investment.

However, I come back to the original point. It *was* working. Or
are you perhaps not so sure now?



I'm reluctant to have cavity wall
insulation if there's a chance that I end up with condensation when
there might be little heat escaping anyway?


That happens if you seal up the house by going overboard on draught
proofing and fitting double glazing and not having ventilation.
Having cavity insulation may result in more window condensation
because these now become the coldest surfaces.
It can be resolved with having ventilation, avoiding release of too
much water vapour (e.g. drying clothes on the radiator) or a
dehumidifier.




--

..andy