On Wed, 30 Jul 2003 16:25:10 +0100, "Christian McArdle"
wrote:

Now I have a question - Maybe not in the regs, but I thought it
was considered 'best practice' to have the mix I went for -
TRV's in some places, and a room thermostat for overall control
(along with a conventional timer). And preferably a programmable
stat. I just can't find the reference for that information ATM.

Not "best" practice, but probably the most common one, and compliant with
Part L. The regs seem to suggest you have to have independent control of
living and sleeping areas. It suggests that TRVs, room thermostats or other
devices can be used to achieve this. It doesn't say what method is best.

The "best" method that is easy to make from commonly available parts is to
zone off each room and have each have its own programmer/thermostat so that
each room can have its own time and temperature settings. (i.e. dining room
could be set to run on boost only before you eat (unless you eat religiously
at the same time every day), bedrooms off until 9pm, then warm, but getting
progressively colder through the night etc). Not a TRV in sight in such a
system. Outside temperature compensation is good too, if it can be made to
work with a multizone system.

The absolute best system would have analogue temperature sensors in each
room, an analogue outside temperature sensor, analogue valve actuators on
each radiator, analogue power request signal to the boiler and pump,
analogue sensors on the flow and return lines, and a little computer box to
take the inputs, compare with your required temperature profiles for each
room and drive the actuators, boiler and pump as required by a very
complicated set of algorithms (probably neural net based learning type) that
predict temperature changes, pre-empt required temperature changes, prevent
boiler cycling and keep each room precisely at its individually selected
temperature, within the capability of the system to do so.

Christian.


I'm in the middle of implementing just such an arrangement of
controls. It's helpful to be able to take data from the boiler to
determine what it is doing, since I want to take advantage of its
capabilities rather than fighting them.

The algorithms are certainly the most complex part, especially when
you have rooms used quite variably.

Temperature sensing is very easy as is the analogue valve actuating
part.


..andy

To email, substitute .nospam with .gl