1: There are available replacement valves for radiators that have a 
temperature setting at the valve and a remote sensing bulb. No power or 
electronics needed. Have seen on "Ask this Old house"

2: Where we are zoned and humidified, I have an issue with condensation 
on walls and windows when the zone is minimum temperature (55F) and 
outside it is say below 0F. My plans are each zone to have a thermostat 
with both temperature and humidity sensors with a PIC connected to a 
central PIC with RS-485. Each zone thermostat would only function to 
send sensor values to central, allow setting the desired temperature 
levels, and display present and set values. The central PIC would save 
the values, do equipment control (heat/cool/humidity), calculate (maybe 
lookup table) humidity set point dependent on actual temperature. I too 
like the hardwire network, and RS-475 isn't that hard with say an 
18F1320. I have one that communicates via fiber optic to a convertor to 
the RS-485. It wouldn't be that difficult to control anything from any 
where.

Bob wrote:
> Hi all,
>
>  
>
>  
>
> With the rise in heating fuel costs I have thought about using PICs to
> control the radiators at home. 
>
> I have some ideas but would appreciate any tips and shortfalls to my ideas. 
>
>  
>
> I would be looking to control 6 rooms but I don't want to go to the hassle
> of ripping up the floor and fitting zoned manifolds etc. I was thinking of
> controlling each radiator on a room by room method with each room
> controlling its own temperature. A central 'controller' would communicate to
> the rooms with on/off and temperature settings. My thoughts about how to
> start are:
>
>  
>
> 1.	Each room has a PIC controlling the room temperature and on/off
> times receiving these settings from a central controller possibly using RF?
> 2.	Central controller would look at outside temperature and adjust on
> times to suit. Different on /off times for each day of week.
>
>  
>
>  
>
> The heating system is about 15 years old and service bi-annually. It just
> doesn't warrant the cost to change the boiler etc. spending 1,000's to save
> 100 per annum!
>
>  
>
>  
>
> Thanks,
>
> Bob
>
>  
>
>   
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