how long for blower to run after heat call done?

BlueBSH

My 125k BTU/h furnace has settings to let the blower run after a heat call for 60, 90, 120, and 180 seconds... how do I determin what is best? it was initially set for 60 but the furnace and metal trunk ducts were pretty hot after the blower stopped...

I changed it to 180 to see how long the hot air flowed afterwards, and it seemed like it stayed at least warm up till 2 minutes then started to cool down drastically, should I have this set to the point it blows till the warm air stops or halt it before it gets to room temp air flow?

what do you guys normally do? I want to push as much as the heat I produced as possible into the house so its not just a hot heat exchanger sitting there slowly cooling off into the basement furnace room only.

Marty S.

Try to hit 80- 90 degree supply before the blower goes off. Sounds like 120 seconds should be about perfect for yours.