I wish to close and open voltage free contacts remotely from a Thermostat downstairs to the boiler upstairs.

The thermostat has voltage free contacts which close and open according to temperature and I want to relay that via rf, infra red or bluetooth from small battery operated transmitter and reciever.

Has anyone any "off-the-shelf" or "done that before" or other suggestions, please

 

What do you mean by 'voltage free'?

 

You might want to think about Zigbee instead. You have to consider the obstruction between the rooms first and check whether this will work.

There are ready made Zigbee modules and design, such as Crossbow or Motes/TinyOS.

Another option is to go with X10 over power line, which will eliminate the problem of walls obstructing the RF signal. There are also ready-made X10 control modules available.

 

How about a Remote Garage Door kit..(hand held transmitter and Separate reciever). The receiver will have relay outputs.. that could work your Control contacts, and the system can be encoded for semi-reasonable security. UHF kits have ranges varying from tens of meters to hundreds of meters, and there are even some HF units about with even better range.
The receiver would probably need to be connected to power, but the transmitters are portable, compact and reasonably reliable.