I have a Comfortmaker Nat Gas Furnace ,6 yrs old; furnace cuts on when thermostat calls for heat and cuts off when temperature is reached; I noticed while heating yesterday and continuing today, a "clicking" noise in the furnace while it is running , occurs about every 2 minutes; to me ,it sounds like a relay kicking in and out.

Have any of you folks experienced an occurance similiar to this?

Thanks for any advice.