On Jan 17, 9:22*pm, CJT wrote:

I suspect 70 is too low. *If you set your thermostat for 74, how would
the fan ever go off? *The intake air would be over 70.

Thanks. I didn't mention in my OP that I also have a wood stove
ducted into my furnace hot air plenum. The wood stove has a blower
that pushes hot air into the plenum. The delema I've had with this is
that when the furnace fan runs, it nearly overpowers the wood stove
blower such that I need to really maintain a pretty hot wood fire to
keep the air warm coming out of the registers. I have tried to power
up the wood stove fan but then it seems to take the heat away from the
wood stove too much and it becomes more of a cycling problem. Either
I end up having to run the furnace fan continuously or shut it off
completely. If I run the furnace fan continuously, usually in the
coldest weather (below zero degrees F.), The house will stay fairly
warm but in warmer weather above zero degrees F the house will get way
too warm and I have to shut off the furnace fan completely. Thus its
a continuous on or off cycle with the furnace fan switch. I was
wondering if I could adjust the furnace fan limit switches so I
wouldn't have to be shutting the furnace fan off/on so much. The oil
furnace is a late 1970's model so I don't think the hotter plenum
temps adversely affect the plenum when the furnace fan isn't running.
Also, I wouldn't want to make any drastic changes to the oil furnace
controls so it will run properly when we are not at home and no fire
in the wood stove. Any ideas on what I could do to make this system
work better would be helpful. Thanks again!
Steve