Often time, one of the most dreaded of all maintenance task done to a furnace is changing out fuses in the coldness. It is a fact that most all furnaces due to similar problems, blown fuses at one time or another through their lifetime use. A Goodman furnace keeps blowing fuses for several reasons.
When the 3amp control fuses blow, a check on the thermostat wires may be the culprit. Shutting the system off and testing the voltage is a good start, as this may be an indication that the voltage is low enough to short a circuit.
If this is not the case, a 5 amp fuse may rectify the problem of why a Goodman furnace keeps blowing fuses. If the fuses continue to blow, check the limit switch at the place where it enters the furnace.
Sometimes a furnace will start a frequent pattern of blowing fuses because the heat exchanger is being pushed by the fan, subsequently heating up the limit switch and blowing fuses.
Taking the time to locate the limit switch housing, removing the screws and bending it slightly away from the heat exchanger will more than likely take care of the fuse blowing problem. According to a HVAC technician, there should be a clearance of at least of five inches between the limit switch and the heat exchanger.
A homeowner can distinguish a blown fuse by the color of the blown fuse, which should be dark purple looking and clearly damaged. It is recommended that a homeowner take the time to completely shut the power off to the furnace before attempting to take out or replace any fuses. Make sure the manual dictates whether to be using a slow-blow fuse instead of a fast acting fuse, which tends to be blown under the most normal of start ups.
Any visible notching or frayed wiring leading to the thermostat should also be checked and ruled out as possible culprits. The most unfortunate reasons why a furnace will keep blowing fuses may be located inside the furnace itself.
When a short-ground wire from the thermostat to the furnace results in the fuses not being blown, than the homeowner can rest assure the problem was indeed a low voltage problem.
If the problem persists and fuses for the furnace is still being blown, it may be time to call a certified HVAC technician to the scene. The original HVAC installer would have left a visible sticker on the unit with any needed contact information. If the HVAC installer can not be found call the nearest dealership and talk to a qualified technician about the problem.
Another way to check to see why a Goodman furnace keeps blowing fuses is to establish exactly the location they are blown. A homeowner should check to see whether the location is on the low voltage side or the side of the furnace control circuits that houses the high voltage.
The amount of current that is being drawn when fuses are blown may have to be check by a certified HVAC technician, to fully understand why the Goodman furnace keeps blowing fuses.
Originally posted 2010-12-31 08:26:40.