Hi folks: I have a Dayton forced air furnace, approximately 7 years old. The issue I've been having is that the fan runs for an extended period of time after the burner shuts off. There are times when it shuts off within a reasonable amount of time, and other times where it seems to run for hours, essentially blowing cold air. The fan also comes on too early. Clearly a temp related issue. I'm thinking limit switch. Unlike my other furnace in the house, this one does not seem to have a control box with the manual on/auto button. The only thing I see related to the fan is a small timer, adjustable from 60 to 200 seconds on the fan motor housing. This was adjusted from near maximum to the halfway point, and I have not seen any effect whatsoever. I'm assuming there must be some kind of limit switch that tells the blower motor to shut off at a certain temperature, but I don't know where to locate that. I can get a model number of the furnace, but this is an upflow, 110K btu Dayton brand that was purchased from Granger. I think they still sell a similar model. I've had the service guy out once, but he was of no help. I'm hoping just to find the part, and try to replace it myself. At several hundred dollars for a service call, I'm not impressed with the local guys knowledge. Troy

Hi all, newbie homeowner and newbie on this forum here. I have a 15 year-old Trane XL 80 gas furnace and I had it serviced a few months ago. The service seemed quite comprehensive, and the technician said it's still in good condition except for some "inducer corrision". However, the duct cleaner came yesterday and commented that my blower compartment was caked in dust and he said most likely the blower motor is similarly clogged - I started questioning the servicing was not as comprehensive as I thought. As it is cooling down in the Northwest, the furnace is starting to kick in during the evenings, and last night, I cranked up the thermostat to warm up the house. I set the thermostat to 72F against the current room temperature of 67F and the furnace fired up. As usual, it started burning and blowing in the lower setting for a while, and then it switched to the "high" mode and the blower started blowing in the higher setting. However, after a minute or two in the "high" mode, I started hearing some clicking sounds from the furnace (sounded like relays clicking on the control unit). The clicking was intermittent but erratic with no fixed pattern, but what worried me more is that it sounded like the flame "choking" as if it's on the verge of distingusihing and then burning again. Also, it seems like the clicking sound is somewhat synchronized with the choking of the flame. First and foremost, I'm concerned about whether the furnace is still safe to use. Then, I'm interested to see what might be wrong with it so I won't be at the complete mercy of the furnace servicemen when they start recommending various [costly] repairs. A few uneducated guesses: - is there not enough air/oxygen for the "high" flame to burn (I heard there is a "booster" to feed air into the combustion compartment)? - is there not enough gas to sustain the flame (I have a 3/4" gas line for both the furnace and warer boiler) - could it be a bad control unit? (but the low setting seems to work just fine) Any help, advice or even educated guesses would be appreciated! Thanks much, - K.