I'm trying to figure out how to connect a Shelly 1PM to my Mechanical Ventilation Heat Recovery (MVHR) fan so I can control the fan speed via WiFi? The unit is designed to run constantly in a "normal" mode but it can be set into "boost" mode by switching a seperately mounted switch which is wired to the unit. So the switch doesn't do "on and off", it's "normal" or "boost".
I've wired up a Shelly 1PM to turn the unit on/off completely (and power monitoring) and this is working fine. However, I now want to connect a second Shelly (Shelly 1) to switch between "normal" and "boost".
This is the diagram from the manual of my MVHR unit (Vent Axia HR100R) showing how to connect the NBSW (Normal Boost Switch), which is a switch which would be mounted in another room. This switch just has "common" (240VAC) L1 (normal) and L2 (boost) inputs so the switch simply bridges the "common" (live) to either the L1 wire (normal) or L2 wire (boost). Both these lines go back to the unit.
So how do I hook up the Shelly 1 now to switch between normal/boost? I would guess N goes to my other neutral connections, L goes to my other live connections (so Shelly is now powered) and O goes to the "boost" wire. However, not sure about the others.
Is this even possible with a Shelly 1? Or do I need something else? TIA