Central heating system heat up to desired temp, after instead of stopping it still blows cold nouns,? i have the switch on auto, the ac works fine it...

i have the switch on auto, the ac works fine it go down to 72, then stops until hotter later cools again,
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Answers:    There can be a problem with the fan/limit control sticking or the furnace control board. For more info including a troubleshooting guide, check out the furnace page at my source.
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within is an adjustment inside your thermostat like a small dial, beneath the regular thermostat. it has a set of numbers on it which represent the time for the supporter to run after the furnace has shut past its sell-by date the heat. This is so at hand is no wasted warmth just limp around in the furnace. Adjust the timer rather at a time to shorten the time for the fan to run.