OK Paul, I've rceived your email, but haven't studied it yet. It dawned on me while pondering about it that indeed the relay on the left is redundant, the power running the WH fan would simply run the Aux vent, then shift to the second WH if it required the power. Elegant. And I had two engineers stumped for a while on this one... (I've got the drawings from one of them and two ice cubes waiting at the job site, but hey, if I can do it with one...).
I did come up with the above configuration on my own, I haven't seen the EE's configuration yet.
Are you control gurus laughing at me?
I'm going to look at the one Paul sent me now... BRB...
