Re; Keeping your Furnace running. Good for you for keeping it going.No it was only a 30 gallon water heater for the inside hot water. But with the gas turned off to do that I would have to relight the furnace for heat. But my brain wasn't working evidently because it didn't compute ? gas turned off=pilot off to furnace ? the furnace is very old but very efficient. I wouldn't want to replace it and would really like to keep fixing it if possible. As it turns out they evidently disturbed a wire to it because even with the pilot lit it won't fire up. But at least I know to use an alternative heat tonight ahead of time. I'll just turn on the oil filled electric heater for the night on low and it will stay warm. This house is so easy to heat and cool it makes the new stuff look stupid. The morning sun comes in the back side windows almost all day and then around 3pm comes through the front windows until sundown. That's winter and summer. It works but I have to keep a window partially open when I sleep for fresh air most days.?
I did 10 years of service calls on Forced Air Furnaces & Hydronic Boilers @ NAS Alameda. Furnaces are easy to keep running. Only 2 reasons I personally would retire a Furnace, One - The Heat exchanger inside has cracked/failed, that would allow C0 to enter your home, the other would be that it is so inefficient that it would be cost effective to replace.
Blower motors, Combination Gas Valves, Fan / Safety Switches are all usually relatively easy to come by.