fuse blown

kingcjfam · #1 May 12, 2007, 01:19 PM

My central ac unit upstair (Goodman-zone 2) keeps blowing its fuse. What troubleshooting can I do to resolve this issue.

hvacservicetech_07 · May 12, 2007, 02:09 PM

Where is the fuse located that is blowing? A little more info on your system would be helpful.

kingcjfam · May 12, 2007, 04:42 PM

My zone 2 equipment is in the attic. At the bottom of the unit, I removed the door and there is a fuse at the bottom. It is a plug in fuse similiar to a car fuse. Once I place the fuse inside of the unit it runs for about 10 minutes then shut off again. I have checked my wires on the thermostat and that is fine.

kingcjfam · May 12, 2007, 04:46 PM

Oh yea my unit is about 4 years old. It is a split system ran by natural gas.

hvacservicetech_07 · May 12, 2007, 04:47 PM

That is a low voltage fuse. Is this an electric furnace? it sounds like you have a short in the low voltage somewhere. Does it blow when you turn the A/c on only?

kingcjfam · May 12, 2007, 05:03 PM

I used the heat this winter but I didn't turn the unit on until last week so I am unsure if this happens with the heat. I have the installation manual what info do you need to help troubleshoot?

hvacservicetech_07 · May 13, 2007, 06:17 PM

Well it could be as simple as a shorted coil on the contactor outside or broken control voltage wire between the furnace and the A/C unit. You need to start by taking the blower door off of the furnace where the fuse is located, on the circut board there will be the following terminals .....C-common, -R- 24 volts usually a red wire, W-Heat usually a white wire, G-Fan Y- A/C contactor, there will be a cable with 2 wires usually red and white that run from the furnace to the outdoor unit, one will be hooked to common and the other "y" , go to the outdoor unit shut the power off and remove the cover those same 2 wires will be connected to 2 wires inside the unit that energise the contactor coil when the call for cooling is made disconnect those wires and be sure to mark them so that you know where they go, turn the system back on if the fuse doesn't blow then you have a bad contactor, if it does blow then remove the wire from the "y" terminal on the control board if it doesn't blow then the cable is bad between the furnace and a/c.



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