Transformer on airhandler (Goodman) keeps burning out the primary side.

[RoBoTeq]

I agree that the problem is more likely on the secondary side. An easy way to fuse the transformer is to cut the hot wire from the transformer secondary side, put insulated female spade connectors on both ends of the cut wire and plug a 3 amp automotive fuse into the connectors.

[pacnw]

could use a new transformer with built in resettable fuse, too.

[waregl82]

I agree with pacnw. I now use a 50va transformer with a resettable fuse. For a few bucks more I get a little safety margin and a resettable secondary fuse. No more manually tieing fuse holders to transformers. Don't know if I am allowed to tell the brand name or not? Somebody let me know if you want brand name.

[jtrammel]

Most times I've found a bad xmfr it was the primary side open or shorted caused by a secondary side short. Bad RV coil is a pretty common cause for lv short.

[littlebigdad]

Make sure you check the wiring outside especially around the wire ties