HAI RC-2000 Keeps Blowing Up

This is the 4th thermostat that Blew Up/Shorted out during a lightning storm when the power in the house has gone off and on.

I can smell the unit burning.

What is my problem?

Do i need a seperate 24V transformer to power the thermostat instead of using the one off the A/C unit?

How would I hook one up?

Can you give more details?

What exactly blew up on your stat? Totally dead? Anything else in your house die? How old is your house? Is your AC unit properly grounded and/or the ground pin of your plug the AC plugs into properly wired?

I'm suspecting something in the wiring of your house or power service to your house.

Dissimilar system grounds between the affected systems will typically cause voltage potential leading to failures like this.

Totaly Dead. House built in 1998. Nothing else in the house died.

Prior to installing the HAI system, I had a carrier digital thermo that worked fine since the house was built.

Will a seperate 24V transformer fix this problem?

Do I just replace the Red (RC/RH) and White (C) wire with the 2 new wires from the 24V Transformer?

You'll probably have to set or clear a jumper so it knows not to use that separate transformer to power the relays. If you screw that up, you'll be getting inside your blower unit which is likely in the attic? When you screw up the wiring on a thermostat, it blows a fuse on that control board inside your unit.

Look for specific instructions for what you're trying to do or contact HAI to verify it... and definitely look at the suggestions from others - I'd suspect that ground voltage potential could be the cause.

Double check your wiring at both ends. Also, look for shorts to sheet metal. Also, check that the 120 VAC is connected properly including the grounded wire.

You can have separate transformers for heating and cooling, but I don't think you can have a separate transformer for the thermostat.

I'm currently on an RC-1000 which replaced an RC-80 because I wanted to update. The RC-80/RC-1000 are connected to the HAI 29A00-1 relay isolation module / Elk 24V Power supply from about 10 years ago.

I wouldn't say though that the additional HAI 29A00-1 relay isolation module / PS would prevent the RC-1000 from blowing up should a lightning strike occur. That said though a few hours after one storm and before our last storm (with much lightning) the AC appeared to be failing. It would run for about 10 minutes and blow the 40 AMP breaker to it.

After much diagnostics and no issues that I could see with the main AC motherboard / HAI thermostat / HAI supplimental relay / Power supply. I started to trace all of the wiring related to the AC unit.

At a loss of trying to figure out what was going on I took the fuse panel cover off and found one of the two AC line posts to the double 40AMP breaker to be loose. I tighted it and the problem went away. I was told that the loose post actually generated heat and weakened the breaker. I'm guessing it was maybe the lightning that weakened the breaker? I do have a commercial style surge protector in place adjacent to the fuse panel.

I also replaced the breaker just on the cautious side of things. The problem hasn't occurred again.

the outlet is connected properly using a tester, and the ground is also good.

i will call HAI tomorrow morning

Have you also looked at the wiring for both the power and the thermostat inside the HVAC unit? This is the most likely location for a problem.

They might recommend their relay isolation product towards the bottom of this page:
http://www.homeauto.com/Products/Omnistat/Omnistat2Products.asp

The HAI relay isolation model 29A00-1 is the one that I use with my RC-1000 with an Elk 24V transformer. Works great.