My furnace runs for 4-5 minutes and then goes off for 7-8 miuntes and then goes on again. My thermostat tells me the furnance ran for 8/5 hours yesterday (30 degrees out) all in very short bursts. I'm pretty sure the furnace is oversized. It's 100 BTU's and my house is about 1700sf and the ductwork is very old. Is there a way to lower the BTU's or turn down the furnace output so the furnace runs longer? It's a Goodman/Janitrol GMP100-3 and I have a Honeywell programmable thermostat.
Repeated cycling can be a symptom of a heat anticipator circuit being off. AS opposed to a quick cycle where the furnace quickly heats the house and then it slowly cools. It may still be oversized but 7 minute cooling time at 30 degrees seems fast.
11:11AM | 01/22/04
Being that the thermostat is a digital, the heat anticipator setting is factory programmed and should not have to be adjusted. This just hides an underlying problem. Check the location of the stat, is it close to a supply register? Try moving it just under or very near a return grille.