[Cara945]

I have a concord 80% efficiency furnace. The fan comes on occasionally but will not stay on for more than a minute. The diagnostic light is flashing a series of 3 lights which indicates a pressure switch or auxiliary limit is stuck open -- how do I find these switches and 'close' them?

[Frdbrkl]

Try changing your filter first, and see what happens. If you've already changed the filter, contact a licensed tech. These are both safeties and should be looked at by a licensed trained mechanic, as an unsafe condition exists and the safeties are preventing operation.

[acetc]

Try turning on the fan at the thermostat to determine if the problem is with the fan motor or a control part, with the fan running turn on the heat and see what happens, Good luck, Mike

[lachoy]

I have a coleman electric heater where is the limit switch located just installed last feb