Dean, try
this document for a troubleshooting guide. Heart Interface is now Xantrex. If you have a remote panel, make sure that it didn't get turned off somehow. Make sure your voltage is greater than 90 volts because the unit will shut down at that point. If those two items check out, I would contact Xantrex at 800-670-0707.
I have a friend that had his Xantrex inverter weld its transfer relay together over the weekend apparently from a power spike.
Let us know what you find.
Here is the
reset procedure for the EMS unit. I would try that first.