We recently purchaced a new home, it has a lennox furnace,which was servuce as part of our purchace agreement. I find that the fan run constantly when the unit is turned on. The oil burner in our other house, also a lennox does not. How can a wiring schematic be obtained?

We recently purchaced a new home, it has a lennox furnace,which was servuce as part of our purchace agreement. I find that the fan run constantly when the unit is turned on. The oil burner in our other house, also a lennox does not. How can a wiring schematic be obtained?
... If your furnace happens to be a new one, the blower will come on before the heat exchanger gets up to a temperature that an older furnace would have. This is done to get the efficiency rating up for the furnace. IF you are saying that blower constantly stays on, then you may need a new circuit board and it may not be a wiring problem. Find a local retail distributor in your area. Go to web site for Lennox and/or Google a question on Lennox dealers in your area. You will need your model and maybe the serial number when you happen to contack your oil/gas company.

If your blower constantly stays on, it might also be the setup on your thermostat. On a mercury-switch type, look for a switch labelled "FAN" and make sure it is not set to "ON". On an electronic thermostat, you would need to determine how to check, and change, the settings controlling how the fan behaves. Not everything is in the furnace!