Our heating system consists of a box outside that uses gas to heat up water in a closed system, that in turn heats air that is blown through ducts and out through vents in the floor or ceiling. We have two blowers, one upstairs and one in the basement and a separate thermostat for each.
When we came home from our trip we noticed that the downstairs blower was on all the time and was sending out cold air when it wasn't actually heating. The kids had been turning the heating on and off while we were away so we were worried that they had broken something so we called the appliance insurance people and we had an engineer here today.
And the problem was - someone had accidentally switched the fan setting on the thermostat to 'ON' instead of 'AUTO'. We had to pay a $50.00 deductible for him to tell us that and switch it back.
To rub salt into the wound, a few weeks ago the upstairs fan had been on all the time and Gary had worked out that the upstairs thermostat had been accidentally set to 'ON' and we'd managed to sort that one out ourselves. I don't know why we didn't think that it might be the same thing again.
At least we did manage to fix the 'flapper' in our toilet over the weekend without needing to call a plumber.