I have thought about it before, tried it with the doser...... that maybe why I bought the expansion card, tried way to many things with these devices, can't remember them allI would first reach out to support and create a ticket and make sure it not a faulty expansion card.
Once you pull the master doser off and enable it has master, which in turn allows you now now to use the temp port and program directly on the device. The P4 will non longer be able to program the master doser and the programming is now done on the master doser.
The master would need a power bar connected to it to control the heater. I am not sure if this possible (may have to actually try this with my master maxi in the basement)
Hahaha