Secondary return pump

[crosshands@hotmail.com]

Good morning.
My customer is wondering if they can control their secondary return pump via their evo home?
They have bdr91’s to control 2 port zone valves for hw and ch. I’ve tried tech support but think I confused the guy! Mind you, I may have confused myself too!

[Richard]

No not possible.

[grog_b]

wouldn't it work with BDR91 set for certain times,
secondary return is just to circulate hw in the pipes to allow hw almost instantly ?
unless i missed something?

[Richard]

How would you bind a BDR91 in and if you could, how would you prevent it overriding the control logic of the evohome controller?

[grog_b]

could you bind it as a heating zone, and just set it to the times you want it to operate?

[Richard]

No, because it will override the heating demands of all the other zones being controlled, especially bad if using OpenTherm.