I HAVE AN OLD CARRIER WEATHERMAKER 58SX. It keeps blowing the 3 amp fuse inside the unit on the control module. It will fire up the inducer motor, light the pilot, but when it comes time to start the blower motor, it blows the fuse and the blower motor continues to run, the inducer motor stops and there is no flame.

Could this be caused by the inducer motor pulling too many amps? I had to remove it and lubricate it for it to run...

Sounds like a board path is shorted to ground. Turn off power & remove circuit board from mount to view back. Look for evidence of arcing.

KC,
Thanks for the suggestion. That is how it all started from moisture collecting above the board and leaking down onto the connection. Replaced board, as it looked a lot like your picture. I have re-checked the new board, and it all looks fine. Any other suggestion is greatly appreciated. If the board is bad, will it always show evidence of arcing?
Thanks,
Mike

Not always, but there are usually some visible signs. Be sure the moisture isn't an issue anymore.

I haven't noticed it anymore. Cleaned out drain tubes, reattached tubes, and sealed up lower condensation reservoir. Did I mention that it is 11 degrees outside? Lovely Thanks again,
I have a new inducer motor on the way and we will see if that helps...
~~Mike

Inducer operates off 120V and so does blower motor and the fuse is on the 24V secondary, so I don't suspect either.

The gas valve is a possibility. Did you try disconnecting the main burner portion of the gas valve?

Kiss,
Please don't laugh at my ignorance, but where is the "main burner portion of the gas valve" and then what do I watch for?
Thanks,
~~Mike

The gas valve is actually two vales in one, that's why there are three leads. A common, pilot and main.

If this is your manual: http://www.xpedio.carrier.com/idc/gr...e=PdfHighlight

Pin #1 of the gas valve is the main burner

You can check the resistance of the coil and also the resistance to ground. Compare it to the pilot valve resistance.

It could be this

Okay, Thanks everyone for all the help. This unit was installed in 1985, 25 years ago. After looking at prices for parts, my time, which is a lot because of ignorance, I have decided to just get a new furnace. It will be installed by a tech. not a realtor like me. Rebates and tax incentives make it cost effective. After 25 years, I figure it owes me nothing. If you ever have a question on real estate... please ask.

~~Mike

Smart move on your part.