I apologize for the rather open ended question..and the long story...

My new (old) home has forced hot air with a Lennox furnace, central air and attached humidifier (Aprilaire). Think it went in around 2006 under previous owner.

I am noticing that the temps in the far bedrooms (whole house is one zone) tend to be a bit cooler than the main living area (where the thermostat is located). I can accept this as the thermodynamics of the home.

That said, I feel like I am seeing something new happening: this past weekend, it seemed to be even colder than normal. Indeed, whereas I usually keep the thermostat set to 74 at night / 72 in the day (manually), I noted the temps in the back bedrooms (which usually will vary from 68 during the day to 70 at night) dropped to 62 degrees.

I checked the thermostat, it was set to 74, but the room was registering 68. The stat indicated it was calling for heat, but the furnace wasnt firing.

I turned the stat to off. Waited a minute, then back to heat and the system started blowing warm air.

I am now noticing (maybe it did this before-- I never checked it) that when set to 74, I dont hear the system blowing until the stat drops to 70. Again, stat shows its calling for heat between 71-73 degrees, but I dont hear the system engage...Is this 'normal'?

I am guessing the time when we dropped to 62 was not normal. But we had a party that day and the door was left open--was wondering if that 'overworked the system', so to speak...?

I've think someone mentioned I have a two stage fan, so I dont know if that factors in to this.

Just trying to figure out if there is anything to troubleshoot here, or if this is just how my system works...Any help is much appreciated

TIA
-K

 

Heating systems are designed to run for hours, so no I don't think it was overworked. First make sure the stat has fresh batteries.