#3 amp fuse series#

Tap and wiggle any sensors that may provide a ground path to the fused 24 Volt source. Or even two wires that may be rubbing to each other. Once the Dim Lamp test is set up ever so gently wiggle any wires that are any where near anything metal. The down side it having the appropriate lamps for every occasion. This gives you instantaneous information and it instantaneously resets if the fault goes away.

When a serious overload happens (the kind that will pop the 'lil popper' or blow the original fuse) the lamps will light up bright. With things working normally the lamps may be dim and may fluctuate a bit as the controller board does its thing. If you get fancy you could use an extension cord too if needed to extend the lamps to other places (NOT using 120 VAC). Have the lamps outside the furnace where they can be viewer from as many vantage points as possible.

#3 amp fuse series#

Since you have the 'lil popper' I probably would put the series lamps in series with the non-grounded side of the secondary side of the 24 VAC transformer. The lamps can be a substitute for the original fuse or the 'lil popper'. The two 12 Volt lamps 'connection in series' gives you the 24 Volts and the #1156 gives a current limit of about 2.1 Amps (close to 2/3 of a 3 Amp fuse). Probably in this case (2) two old school #1156 automotive Back Up lamps Connection In Series. Its is called the Dim Bulb (or Dim Lamp) tester (some videos on YouTube). If I were there, and I was tasked to find your problem knowing the history you have posted here, this is what I would do. I am not a big fan of 'lil popper' type troubleshooting, except it may save fuses.

I believe you swapped out the controller, so the 2nd controller should not be suspect, but 'like' electronics devices often have 'like' defects, keep this in mind, sad but true. Since your problem is happening when the blower is in operation, you should look at that low voltage circuit that operates the blower relay. Since my failed wire was the one that operated the condenser, the problem never happened in the winter. Eventually, within less than 1 minute, the uninsulated portion of the thermostat wire to the condenser touched together and a dead short on that control circuit blew the fuse. A weed-wacker had pealed the insulation off the wire and when the condenser fan moved the air thru the condensing unit, the wire fluttered in the breeze. I traced the problem to the thermostat wire that went to the outdoor unit. I turned on the AC and after a 5 minute thermostat delay, the compressor contactor powered up for about a minute or less, then the fuse blew again. I replace the fuse and tested the furnace and everything was fine. I found that the fuse I added to the circuit failed (good thing I added that fuse). I replaced the transformer for a customer in September (cooling season was over and the heater would not work). Picture of the circuit board with the fuse and or the model number of the furnace might help.įor example: I had a similar situation with a bad transformer. Also, look at the fan circuit thru the circuit board. Look at the green wire from the thermostat to be in direct contact with the common somewhere. That fuse is to protect the transformer from letting the smoke out. the motor winding on the blower motor is line voltage (110v or 220v) and the fuse is on the low voltage circuit.