Started up the furnace last week -- nothing. Batteries in thermostat OK; circuit breaker hadn't flipped off; power switch for the furnace was still on.
I called Len, who came over the next afternoon, and it was up and running in 5 minutes. My bad! Here's a tip: check that the filter is clean! I hadn't changed mine for the fall, and a dirty filter may stop the furnace from kicking on as a safety measure. Oh well, next time! Thanks, Len, for the speedy service, helpful explanation, and cheerful demeanor! The next time I need service, or a new furnace or A/C unit, I'll be calling you.