[sclug] Re: sclug Digest, Vol 27, Issue 5

[Graham]

> Message: 1
> Date: Sun, 04 Dec 2005 16:45:03 +0000
> From: Mark Cooper <sclug at mcooper.demon.co.uk>
> Subject: [sclug] Home automation - Remote central heating control?
> To: sclug at sclug.org.uk
> Message-ID: <43931D0F.7030209 at mcooper.demon.co.uk>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> Is anyone aware of any 'web enabled' central heating control's? I'd like 
> to be able to turn my home heating on or off from work :)
> 
> --
> 
> Mark Cooper
> http://pvrhw.goldfish.org/ - Open Source PVR Hardware Database
> 
> ------------------------------

I know nothing about X10 boxes,
but I am an expert in living with a faulty CH + thermostat.

I decided not to bother, but the thermostat is something like 3 wires
- Always-Earth, Always-Live, Demand-Feed-LIVE,
and the thermostat could be replaced with a relay. (I didnt check the volts) 

I'd have a one hour booster button, and an empty-flat detector.
I would set different temperatures at different times of the day.
I would avoid "switching on and go for broke", by pulsing the demand
as 2 minutes on, 4 minutes off (guess). This takes longer, but (1) it does 
take time for the heat to propagate air/surfaces, (2) warm radiator water
absorbs more from the boiler than hot water, (3) warm radiators are more
comfortable than hot ones, (4) my boilers water-temp-thermostat sometimes
cooks whatever is on the radiator.

I'd also have a programme-mode for when I have washing on the rads
and want a small amount of warmth, but not heat. This counters the
washing remaining damp for a long time, (or corners remaining damp)
which can cause mildew on the walls - and by contact, the cloth.

The next big problem, is what to do when your PC is switched off.
This is an argument for a relatively low power ADSL router, bluetooth,
a bit of extra memory (retained over power cycle) and programability.

I'd also be a bit sceptic about things doing what they say they should.
My room thermostat (on-off tilted mercury thermostat, lynx-potterton)
often gets it wrong, maybe its the cavity wall behind it, but wrong.

On an unrealistic wish list, I'd like to get info from the boilder,
such as when it is burning hi/lo flame, pump is on (it continues
after demand + flame are off), and water demand (auto detect bath + bed cycle)
so that I could calibrate its metrics and behaviour against other things,
to develop better programme-cyles.


Graham