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Troubleshooting often requires meters and test equipment.Do you have a multi meter for testing voltage? If not you can get an inexpensive one at Walmart for about 15 bucks, if you have or would like to obtain a meter to troubleshoot , I will be happy to guide you.Without a meter , there are a limited number of things we can check if you are able to do a visual inspection and can do some hands on troubleshooting.Please let me know and we can go from here
Those little light testers usually will not light up with 24v.. Lets do this.
Take a jumper of some kind and jump R to W )(thermostat wire connections)on furnace control board and see if heat will come on and R to G and see if fan will come on.
Should be the same unless we have a break in control wire between tstat and furnace.Depending n model of furnace you may have a small 3 or 5 amp fuse on control board that could be blown.If you can grab a meter on the way home we can troubleshoot.Keep I mind though that if fuse on board is blown or thermostat is burned up, there could be a short somewhere that caused it to pop.Simply replacing fuse or transformer may result in burning new one.Short will need to be found and eliminated.Shorts can be difficult to find unless a wire is bare and touching such as being chewed by an animal or hit by a weed eater .I recommend once we find if it is fuse or transformer that we get several fuses for troubleshooting.
Older furnaces did have the fuse on the board .It is a good possibility transformer is bad if we have voltage to transformer, but nothing will come on. I recommend we put a fuse in one of the low voltage wires when we replace it just in case there is a short. Get a pack of 3 or 5 amp car fuses .See below:
I like to troubleshoot and verify .If you can grab a meter,that would be best.AS for transformer and the fuses, you can get at any appliance parts store that sells washer,drier and refrigeration parts.A standard 40VA 120/24v transformer should be less than 20 bucks and a box of fuses as shown about 5 bucks.
I am usually in office until 9 or 10
Sounds good.Look forward to working with you
Sure,Look in burner compartment and get me model off of label so I know exactly what we are working with.
OK set meter to check AC volts 200. Then check for 120 in between white and brown and for 24v out between black and blue.
Ok transformer is definitely burned up then. I would put a fuse in one of the low voltage wires when replacing. Also look good for any chewed or cut marks on control wire between furnace and thermostat and outdoor unit and furnace.
Power surge, wires touching somewhere, wires connected wrong at thermostat, or a shorted component such as contactor,thermostat or fan relay.
That is correct fuses are much cheaper than transformer is why I like to have the fuse inline.