On 10/29/2013 8:53 AM, cln wrote:
My 18 year old house has a combination Wood and Electric pushed air furnace.

I'll start a fire and eventually the fan starts... typical and expected.

I question what follows. The fan will run for 1 to 2 minutes. In the beginning the ducts barely have time to warm up so the air isn't hot when it comes out.
After a few minutes, the fire is roaring and produces plenty of heat. I even added a tiny 4" fan on the flue pipe to propagate the heat in my shop.

So if this 4" fan is enough to make a small difference in my shop, why isn't the furnace running longer at times?

I had the furnace inspected last winter/spring time. A fuse had popped. He checked it over and said there was nothing wrong with it.

Is there something I can do? I asked if the fan could be upgraded to a two speed fan. I figured that it could run on a lower temperature.


Any advice appreciated.


My last DIY thought was to attach 2x 4" fans on the duct outlet in my shop and having it on a 4-6 hour timer. Fans were free and both would cover a floor vent type duct elbow nicely... this way less of the heat would be wasted up the flue


Is the short run by design? Or is it a bad thermal relay that is
shutting it down? You can hook it up to run as long as s certain
temperature is reached.

Is the fan taking heat from a heat exchanger or directly from the burner
where it could cause an overdraft? Many possibilities here.