I have a (to me) weirdness in my heater/air conditioner system. I live in a high-rise building, which is about 3 years old and my apt. has forced air HVAC. Everything seems to work as expected but there’s this one thing….
Every so often, say every 2-4 hours (it’s so “random” I’ve never tried to time it), the fan will fire up. The fan will operate for 10 seconds or so and then shut down. This happens in summer and winter (i.e., it appears to be independent of whether I’m using AC or heat). Since my apartment rarely varies much in temperature (good insulation?) I rarely use the HVAC system which is why I notice this.
Here’s what makes it weird: it happens when the thermostat is turned off. Every domicile I’ve ever occupied only uses the fan when actively heating or cooling (some folks, of course, set the fan to always run, not I). With the thermostat off, there shouldn’t be any activity, right?. If the thermostat is on then of course the fan fires up to heat/cool but how come it comes on sporadically with the thermostat off?
Any HVAC folks have a SWAG? Is it some kind of code issue where the air has to be shoved around to insure it doesn’t get stale? The water heater (a really big mother) is in a utility closet within the apartment so maybe the architect was concerned with CO2?