I have 2 wire thermostat controlling a window ac using 220 v . I replaces the burnt out 24v transformer . The AC worked but when I turned of the thermostat and then turned it back on the new transformer heated up and stopped working again . I replaced it again and the new one also burnt out . (3 transformers wasted ) could there be a problem in the relay , PLEASE HELP

I have 2 wire thermostat controlling a window ac using 220 v . I replaces the burnt out 24v transformer . The AC worked but when I turned of the thermostat and then turned it back on the new transformer heated up and stopped working again . I replaced it again and the new one also burnt out . (3 transformers wasted ) could there be a problem in the relay , PLEASE HELP
Are you replacing this transformer with one exactly like the original? Is it a 120/24 or 220/24. Check the booklet that came with the thermostat and make sure you are replacing the transformer with the correct one.

First I would find out why the transformer is blowing rather than just replacing parts. I would also suggest putting an inline fuse in to protect transformer. Lot cheaper to replace fuse. Next I would check my low voltage wiring. More than likely you will find one shorted out causing this problem