On Friday, August 1, 2014 9:44:01 AM UTC-4, wrote:
trader4 says: " It seems like they have established their own neutral,

unconneced to the service neutral, going to the other units. "



My assumption is that this is not a self-establised neutral, but the wiring control (from the indoor evaporator) that tells the outdoor condenser to switch from A/C to heat pump.



I was thinking of it strictly in terms of power and the fact that in
the diagram, that wire is marked N(1). Marking it N and having it wired
right there with the two hots, sure strongly suggests it's a neutral.
Do they talk about what that N(1) means at all?

But if those wires are the only link between the outside and inside eqpt,
then I agree signalling would have to go on it. It's even possible it
serves both functions, but if it's like you're suggesting, it makes sense
electrically. But if it's signalling, I wonder what code says about
that? ie, combining signalling, which would normally be low voltage with
240V? I guess it they use 240V to do the signalling, then it's OK, but
they couldn't AFAIK use 24V or similar.

Regarding using 240V to run the evaporators inside the house, I'd have
no problem with that. In Europe, many places, 220 is standard receptacle
voltage. Also, something many folks miss, it's pretty hard to wind up
with 240V going through you. You'd have to make contact with *both* hot
legs. Far more likely is standing in water, touching ground and one hot,
in which case, it's still 120V.