I've got a sta rite 400 heater never quite been right since we got the house. I've replaced the thermistor 2 times over the last 4 years but this year the led for the gas sensor was illuminated so I replaced that. Funny thing is while I'm changing that I notice the marking for all the wires to all the sensors are mixed up.
The ags wires were going to the thermistor the thermistor wires were going to the high limit and the high limits were ran to the ags sensor. Upon landing the correct wires to the correct sensors now it starts up the fan for a about 10 seconds then just constantly cycles the fan that's as far as it gets.. And now the Afs led is illuminated. I'm thinking air switch but I almost wonder if my board is bad the Fenway unit is good I've checked all the outputs and inputs on that so I'm thinking maybe the main board is scrambled and they had it wired wrong to fool it and make it work or ? Hate to just throw $ at it . Anyone ever have similar issues