If you go to OC and OL at the wall control, it's in parallel there, and the wall switch would also work. That's how mine is setup. The main HRV wall control lights up (to indicate the HRV is running) but I'm pretty sure the timer/remote boost switches are powered and operate independently. They are only powered and flashing to indicate operation at each individual boost switch. I just sorted a wiring mess in a home with 5 of those remote/boost controls. I'm about 99% sure the other 4 remote switches don't operate/indicate when one of them has been activated, but the HRV main wall control does indicate ventilation/operation if the unit was off.
@hubitrep , are you seeing something different? I have never tested jumpered OC/OL terminals at the HRV to see if the remote boost switches indicated anything. My personal setup used a Fibaro smart implant on OC/OL at the HRV itself, no remote boost switches so I can't test this. I've also removed the Venmar fan and am using external EC fans x 2 controlled with 0-10v.
