Generac expert needed
We have a 25kW Generac (Elite 5324) feeding two 200-amp automatic transfer switches. It is mounted inside a very large mechanical room (several feet of clearance on the nearest side). The room has a large (3x3) motorized intake vent and an equally large exhaust fan setup. The area of these vents is calculated at approximately twice the area required to supply adequate ventilation while the generator runs, and they are aligned with the generator to provide good constant airflow directly across the unit. The generator actually runs noticeably cooler inside this room than it did in open air. I did quite a bit of research on how generators are installed indoors before the room was designed.
Right now we use the generator on manual start so that I can flip a switch to open the vents and start the exhaust fan. I have wired these to both a switch and a relay. I had hoped to pull 12V from the generator engine as a trigger so the vents would open and the fan would run during the exercise and cooldown cycles, as well as during actual power generation (and eventually I'll also wire a discreet indicator light inside the house for when the generator is running). I do have a zener diode in there, too, to prevent an induction spike when the relay opens.
However, I can't find a good +12V source when the engine is running. The alternator fluctuates too much, pulling from the coil wire interfered with ignition, and the only other wired item was the oil pressure sensor which is a very low signal voltage. I suspect I could pull a signal from the electronics side of the generator, but I don't know enough to go poking around in there. That's where my request comes in:
Can someone advise me as to how I might accomplish tripping that relay? It doesn't have to be 12V... if I can get some other voltage, I'll just buy a different relay (although I'd prefer 12V since I've already spent $30 on this one, and it's already wired up).
Again, I want a trigger ANY time the engine runs, not just when it generates power (otherwise I look for a way to run 110 on the house side of the transfer panel).
Generac refuses to discuss it since this is not within their installation guidelines, and I can't blame them, even though it's frustrating. Incidentally, the genset is out of warranty, so that isn't a concern.