[railgrab]

I've quickly blown two 110 to 24v 40va transformers. This transformer powers the electronic dampers from my furnace. I have 2 zones, 2 thermostats. I've also had problems blowing the 3amp fuse in my furnace itself when activating my zone 2 thermostat. All three of my damper motors test out OK, as well as the main board for the damper controls. Could a wire from my zone 2 thermostat cause both these problems even if they test positive for continuity? Also, since my 40 va transformer is rated to 1.67 amps, should I use a 1.5 or 2v inline fuse? Thanks thanks thanks! Ethan

[labman]

The wires could have OK conductivity. What you need to do is make sure the resistance between them equals the resistance of the motor or whatever they feed. I lost a couple of transformers after chipmunks chewed the insulation off my thermostat wires. Try to inspect the wires their intire length. Use the 2 amp fuse. It should still blow before the transformer burns out. Might add up the loads and make sure the transformer has a little margin over the total at any one time.