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[hhc11]

I just purchased & installed a US stove 1600 EF outdoor forced air furnace to heat my 3000 sq ft pole barn. It does a great job of heating, but I am having trouble regulating it. I can build a fire & set the thermostat on 70 degrees, it comes up to temp & the motorized draft closes, the furnace cools down & blower shuts off. Then in about 10 minutes the blower comes back on even though the thermostat isnt calling for heat. It will run for a minute or two, shutoff & repeat. I called US stove & they sent me a new honeywell fan control. It is set at fan off 100 degrees , fan on 150degrees & hi Limit of 200 degrees. I changed the fan control & saw no improvement, they also sent me a forced draft blower to replace the motorized draft control. I installed that & still have the same problem although not as bad.
 I gave up on US stove tech support , I ran thru the wiring schematics on the stove & the way it is wired any time that
the airbox temp exceeds 150 degrees the blower activates whether the thermostat is calling for heat or not, I assume this is a safety feature so as to not overheat the airbox. The tech at US stove says the only time the blower should run is when the stat is calling for heat, but it cant be the way it is wired. I think that the draft is not shutting off tight enough & it is still burning enough to raise the temp past the 150 degree set point. The fan they sent has a panel that slides t uncover the opening to regulate the amount of air allowed to the fan, but when the fan stops blowing air can still be pulled thru the fan as a natural draft. Do I need to add a motorized flap to shut off air to the fan when the fan isnt running?

sorry for the long winded post

hhc11

[mopar969]

How many cords do you use in that thing, how big a house, what temp do you keep it and where you live at?

[Scott7m]

Not gonna find much info here on an air furnace.......

were all water guys in here...

[slimjim]

I'm a boiler guy but do know enough about hot air to understand your post, you are right about the forced air blower, it should come on any time the furnace gets to its setpoint-150 and should shut off at its low setpoint-around 100 degrees, this is usually acomplished using what is called a snapdisc that is placed on the jacket aka heat exchanger, that part all sounds right. You seem to be having trouble with the fire overheating the heat exchanger, the # 1 reason for overheating is that the air never shuts off on the intake side, here are a few reasons this may be happening, tall stack increasing the draft and pulling the air in through the intake system, door gaskets leaking allowing fresh air into the burn chamber, draft control inoperative, if you have an extended stack on the stove you may want to start by checking the draft, it should be about .10 inches in a water column (manometer) your oil service tech can check this for you. If the draft is to high it can be reduced by installing a barometric damper on the stack( the flapper on an oil boiler or furnace) your oil service guy can help with this as well, if you have any more questions you may PM me with your phone # and we can talk.