Fusible link melted!
You guys are embarassin' me. I've made my share of mistakes, and still do
Here's one I made years ago:
Late one night, "no heat" call at a !!!CHURCH!!! So I roar down there and determine that the combination fan/ limit switch is bad, go out to the truck, throw one in, and stand there and watch as...................
the control transformer, the gas valve, and the thermostat all go up in smoke
WHY?
Because Honeywell "universal" fan/ limits come with the fan and limit switches jumpered together at the common point of the switches
Some furnaces have the limit in the 24V control circuit, and some are in the 120V transformer supply. I neglected to check this, did not cut the jumper, and so I got to replace ALL those parts...............fer free
You guys are embarassin' me. I've made my share of mistakes, and still do
Here's one I made years ago:
Late one night, "no heat" call at a !!!CHURCH!!! So I roar down there and determine that the combination fan/ limit switch is bad, go out to the truck, throw one in, and stand there and watch as...................
the control transformer, the gas valve, and the thermostat all go up in smoke
WHY?
Because Honeywell "universal" fan/ limits come with the fan and limit switches jumpered together at the common point of the switches
Some furnaces have the limit in the 24V control circuit, and some are in the 120V transformer supply. I neglected to check this, did not cut the jumper, and so I got to replace ALL those parts...............fer free
