[cowboy1973]

My, carrier indoor air handler keep shorting out low voltage transformers. I've replaced 2 of them, the system will run for about 5 hrs. before it shorts out. Thanks.

[2laredos]

Check Wiring Going To The Condenser ( Outside Unit) Somewhere There Are Touching Wires 24 Volt Going To The Air Handler. Use A Multimeter If You Can.

[KidChaos]

My, carrier indoor air handler keep shorting out low voltage transformers. I've replaced 2 of them, the system will run for about 5 hrs. Before it shorts out. Thanks.

Its easier to simply run new low voltage wire to the condensing unit,
It takes almost zero experience, its 2 wires to the condesing unit, and 1 of them(common) can be grounded! So its pretty easy to say what's grounding, just not where precisely, its easier and better to replace the wires as they are touching a metal penetration usually and barely /intermittantly allowing a slow bake, this is if your transformers big enough? What VA are you using? And what's the amp draw when energized in ac mode? If you have a 40VA its about a 1.75 amp capacity before it bakes, I use 75VA transformers on everything and they even have a resettable circuit breaker on the 24v supply side if it blows no biggee! Better get one!too

[KidChaos]

Now I remember a unit with debris that fell into the contactors coil and allowed a high amp draw to exist but not bad enough to smoke it instantly, some shorts happen in specific modes like heat lumps but AC alone is 2 wires Y or yellow from the tstat and C or common on the transformer as easy as it gets!

[KidChaos]

Basically chack the amp draw on the trnasformer after its fired up, then see if the contactor coils shorted or going bad? A contactor a few capacitors and a coil cleaning will stop most AC emergencys, oh yes a few time delay fuses too simple cheap DIY things that you kick yourself for after calling a guy.