Lennox G40UH running when not required
I have a 5 year old Lennox G40UH gas furnace. The furnace runs for short periods (2-3 minutes) 10-15 times per hour. This happens even when the house temp is above the thermostat setting. I have replaced the thermostat but the problem continues. I have checked the diagnostic lights before, during and after these short cycles and they always flash normal. If the thermostat is turned up a couple of degrees, the furnace runs normally until the desired temp is reached. Only then does it seem to start this unnecessary cycling. Any ideas? Thanks Paul