# Thermostat wires sparked,no AC



## justjoet (Aug 2, 2012)

you actually might have either shorted out your tstat, or your transformer, or maybe both it is crucial to always have all the power off when servicing a system, whether it be just a tstat


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## raylo32 (Nov 25, 2006)

Look at the air handler control board for the little 3 or 5 amp transformer fuse. It is likely that all you did was blow that. Replace it and you should be good to go... assuming you get the stat wired up correctly. As the other poster said, have the power off whilst doing the wiring to avoid this sort of problem.


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## biggles (Jan 1, 2008)

and why didn't you shut the furnace toggle off? if red touched the C terminal you cooked the transformer. if anything else might of blew the fuse on that circuit board hope you have in that furnace.if you can run the FAN/ONLy from the stat your good on the TR 24Vs if not LEDS or fan action the 24Vs isn't happening.check the fuse on the board.if you have an ohm meter disconnect the primary and secondary sides of the TR an ring them no audible or ohm reading the winding is open.from the spark...


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## ben's plumbing (Oct 6, 2011)

always shut off any electrial appliance before service....may have fried ..tranformer...or blown 3 or 5 amp fuse on control board....:yes:


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