Rad stat and boiler interlock

I’ve got a few StellaZ and a Danfoss in place around the home and a Phillio relay controlling the boiler for HW and CH.

What I want to do is arm the Phillio relay/ switch the boiler on when there is demand from any radiator around the house. I thought this would be simple and must have been attempted before but can’t see any solution. Any pointers or suggestions please ?

I had planned to use combination switch or PLEG to activate the boiler based on the demand, however, there is no “demand” or equivalent on the Stella or Danfoss devices, only set temperature and ambient temperature (on the Stella). Clearly if set=ambient then there is no demand but PLEG and the Combination Switch only allow compares to actual values entered in the plugin(e.g. 22c) as opposed to a variable value (i.e.“ambient value”).

So, how do I do it folks ?

Use PLEG … there are examples on the forum.