______________________________________________________________________ I have been in my house for about three years and my furnace never seemed to heat very well, last year I had somebody look at it and they replaced the regulator and the furnace was heating much better. However the problem I have now is that when the furnace reaches the temp requested on the thermostat and the burner and blower shut off as normal the fan for the exhaust vent cycles on and off about every 5 seconds and will not stop unless I turn it off. Replies: Xenos Webmaster “Re(1):Tempstar furnace cycling on and off” , posted Fri 28 Nov 15:20 ______________________________________________________________________ I do not have access to Tempstars Support. All I can recommend is checking the voltage leaving the board and verify its the board powering the motor on and off. Xenos. The best way to escape a problem is to solve it.