Selgas
You say two things here = you beleive the unit was dry fired – by that I take you to mean it was turned on and the thermostats applied power to the elements with no water in the cylinder if that was the case than it is a fair bet your elements are shot.
If that was not what you meant – then you say you have power to the thermostats BUT do you have power on the outlet terminals from the thermostats to the elements – if not I suspect your thermostats may be at fault – if you do have outlet power then it is not rocket science to suggest your elements are the cause of your grief. 
Selgas Services Ltd
Craftsman Gasfitters, Plumbers, Electrical Service Technicians
