Managed to find the name of the installer and gave them a call. With hints from here and from them I did a little digging.

Checking all the circuit breakers was non-eventful as all seemed fine. Return trip to the water heater closet again showed everything as it should be..

Following instructions from the installer I went to the attic to see if the house inspector had inadvertently closed a valve or opened a switch. Again nothing.

Returned to the thermostat to verify settings. Discovered through the process of elimination that the fan control did not activate when set for AUTO. Instead selecting just the full ON position brought immediate heat. Quickly brought the house to 74!

Leaving the fan selector in the on position I tried lowering the temperature settings. Worked fine.

For now I'm focusing my attention on that programmable thermostat. Figure if she treats it like an older manual variety by raising or lowering directly she'll at least have heat. Just the fan will be circulating air 24/7. I did not open the thermostat housing as I have not found a master shut off switch for the system. Having come this far I'd hate to fry something in the process. Gut feeling now is either the unit was incorrectly wired or perhaps is simply failing.