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JAC53 · Sep 14, 2009, 03:46 PM

I have a Rudd air conditioner Heat Pump, My fuse at my thermostat keeps blowing 3AMP fuse, can someone help me please.

hvac1000 · Sep 14, 2009, 04:04 PM

A fuse can be blown for many reasons

There could be a short in the thermostat wiring anywhere from the thermostat itself down to the furnace and from the furnace to the heat pump outside. I suggest you check that wiring carefully and use a meter to test all the legs/color coded wires to be sure of no grounding or wires touching together type problem. Be especially sure to look outside since dogs and other animals will chew on the wires and cause them to short.

You can also LABEL and remove the wires at the indoor unit without the power on. Then turn the power back on and see if the fuse blows. This will help to indicate if it is a wiring problem or if the problem is in the furnace/air handler itself or the outside unit.

No Matter what you do LABEL the wires so you know exactly where they go back to and also turn the power off so none of the wires touch themselves during removal or you will create another problem.

NOTE if you just replaced your thermostat and it is causing the problem here is a copy of the manual for you to use,

http://s3.pexsupply.com/manuals/1249...620_Manual.pdf
After performing the above post back with your results. NOTE: only replace the fuse with like same value and style. A higher rate of fuse can cause serious damage to the circuit board etc.

JAC53 · Sep 14, 2009, 04:31 PM

Yes, I had replace thermostat from 9520 to 9620 programmable and wiring was matched, Just had unit serviced on 9/11/09 and now it started this problem.

Woud this be cause by blower capacitor or compressor capacitor that AC tech recommended replacement?

mygirlsdad77 · Sep 14, 2009, 05:00 PM

The capacitor will not cause low voltage fuse to blow. A bad contactor could. Get the person back that did the service so he can find the problem.

hvac1000 · Sep 14, 2009, 06:54 PM

I agree with mygirlsdad77 but it seems strange that your trouble would start right after the service person was there. It might be smart to call another company after you see what the original company says. Please post back with the details.

JAC53 · Sep 14, 2009, 08:17 PM

Thanks very much for your help, I have called someone else to check this for me, I will get back with details.

Again, Thanks

mygirlsdad77 · Sep 15, 2009, 03:08 PM

Look forward to hearing what they find. Good luck. Lee.

JAC53 · Sep 15, 2009, 06:39 PM

Service Tech came out and found a black plug that was not inserted back in properly, it was causing the 3A fuse in the thermostat to blow, once re-connected properly the A/C is working fine now. Thanks everybody for your support. Love the site.

hvac1000 · Sep 16, 2009, 12:57 AM

I am glad you got it running but if it was running before and the only thing changed was to reverse a black plug then who changed the black plug to start with to cause the problem? Just curious.

JAC53 · Sep 17, 2009, 03:59 AM

It was caused by the first service tech that completed the 2nd annual service visit, he had disconnected several connectors and plugs checking for voltages and Caps he did not re-connected back fully it. Manager of company is reimbursing me the service call fee that I paid to another company visit who found problem.

hvac1000 · Sep 17, 2009, 10:07 AM

As I mentioned in my other post ((It might be smart to call another company after you see what the original company says.)) It was a smart move for you to do that. While most companys are honest you never know so if something does not feel correct no matter if it is you HVAC stuff or car etc I would always have someone recheck the work so you do not get the shaft. Glad you are out of the woods and enjoy the weekend.

JAC53 · Sep 18, 2009, 10:54 AM

Thanks 1000