I moved into a house with an above ground pool last August. The pool had a heater attached, but was set up to bypass it by the previous owners. I assumed that meant there must be issues with the unit, but never tested it. A few weeks ago I reopened the pool after the winter, set the valves to run through the heater, and tried firing it up since the water was at a balmy 62 degrees. Everything seemed to work fine - blower came on, the the burner started and heated the pool for several hours. Got it up to about 75 degrees.
However, since then, an issue has developed. When I turn on the heater, the blower tries to come on for about half a second and then shuts off. Then it will try starting again and shut off in a never-ending loop. The service heater light comes on each time it resets. I opened up the unit and observed one flash on the diagnostic light (which, according to the manual means "Air Flow Fault"). I also notice the AFS LED on the back of the control panel is on. I checked all the wiring connections and didn't see anything amiss.
Anyone have any thoughts or suggestions on this? I'd love to save myself the cost of bringing out a technician. I'm a little handy, but not by any means adept at electrical or plumbing.