All done. Tech came out today, installed the battery & MobileLink unit, and plugged in the activation code.
Exercise period set for weekly (10A on Saturdays), initial changeover set at 15 seconds rather than the default 5 seconds at my request (we get a fair number of short term dropouts when weather is dicey).
Did a simulated power out (utility breaker on switch turned off), house switched to gen. power in less than 30 seconds. 5 ton heat pump was on a 5 minute lockout at switchover. Lowered the thermostat inside so it would come on for cooling asap & it cranked up as expected as soon as the lockout timed out. (UPS's chirped at heat pump start-up, indicating a momentary voltage dip - but immediately went back to normal wall power). Could not hear any real difference in the engine whether the heat pump was running or not.
Utility power was turned back on at the switch, there was about a 3-5 second delay & the switch relays fired to change back utility power. Generator continued to run a little bit for cool-down then shut off.
There is a 25 hour break in period for the generator, at which point oil & filter get changed. If exercise + outages don't get 25 hours in the first year, a change is done anyway. After that it is done annually or @ 200 hr intervals, whichever comes first.
Nick