I did play around with the “Vent” wiring (dry contact) this past weekend. It actually worked great with 12VDC - I could set an unbalanced MAX setting and it would use it when the contact was closed. However, as the manual states it completely overrides the wall control. Once the dry contact is opened back up, the ERV is forced back into Standby (off) mode - the only way to get it back to the previous state is using the wall control again which is a nonstarter for me.
However, I discovered that using the VTTOUCHW you can set “Auxiliary” airflow CFM. It doesn’t allow for supply/exhaust independent settings, but if you set it as low as it’ll go and use “Performance” Mode you can end up with a small amount of positive pressure when the OVR contact is closed - which is exactly what I’m looking for. In my case it was ~60CFM which is enough to help exhaust fans work well!
I have noticed the airflow settings on the VTTOUCHW don’t seem to stick sometimes though, not sure why they keep getting reset. Anyone else with this device observed this by chance? Wondering if it has to do with my wonky wiring.