I have a Nordyne 2 stage electric furnace model E1EB-015H we changed the thermostat 3 years ago using a Honeywell RTH8500D. Since this was done we have had trouble every year. I have had Technicians out each season to work on the unit and they get it working until it is time to change from heat to AC or Ac to heat.

The problem is that the heating coils and fan want to run constently. This summer I had disconnected the coils so that the A/C would work, which worked fine except the fan ran constently. Now I need the heat to work and it will except the heating coils want to stay on and again the fan is constently running. I plan on changing the fan relay tomorrow.

Any other sugguestions would be appreciated.

Check the mode of the thermostat (fan/off/auto). In the off position the fan should not run. In the on position is should run all the time. In the auto position it should run if you have a call for heat or call for cool.

With Electric heat, the thermosat controls the fan thus:

Disconnect G at the furnace and see if the fan stops.

If it doesn't suspect the fan relay. If it does, suspect the thermostat or wiring.