I want to add a second thermostat to my oil CH. I want an 'or'
function between them: if either T1 or T2 calls for heat - run the
boiler until neither calls.

As I see it thermostats are switches so just wiring them in parallel
should do the job. Or have I missed something?

R.

TheOldFellow wrote:
I want to add a second thermostat to my oil CH. I want an 'or'
function between them: if either T1 or T2 calls for heat - run the
boiler until neither calls.

As I see it thermostats are switches so just wiring them in parallel
should do the job. Or have I missed something?

R.
In principle you are correct. You might experience some unexpected
effect on the hysteresis of each stat due to the accelerator heaters in
the stats esp. if they are older style bi-metal types. If this causes
you a problem then use each stat to operate a relay and 'or' the relay
contacts.
hth
Bob