Hi Richard, thanks for this
The extraction fan will be a simple single speed, it's either on or off.
I'd like to use the same/similar switch to ensure I never have the Extractor and Heater fans on at the same time.
Positions explained a bit more.
- Position 0 would be Off.
- Position 1 would provide the earth for the new extractor fan circuit,
- Positions 2 provides the earth for the current Heater fan 1
- Position 3 provides the earth for the current Heater fan 2
If this pans out and I reuse the existing Knob and markings on the dash then I'll rotate the switch anti clockwise so that Off will be left of the current O (Off) position, O will be position 1 (Extractor) etc,
I will need at least a 4 position switch, the back of the one pictured looks like a 12 position switch so I was wondering if it was limited to just 3 somehow that could be changed.
Yes I think that you will need a new 4 way switch. I believe the switch at the moment is a fixed 3 way, with 4 poles (so 12 positions total). It only uses 1 pole so will have 3 poles free but I don’t think that will help you. The stop can be adjusted to limit the rotation.
