Backup Thermostats – These thermostats are wired into the Relay Control Unit
and are used only if the computer integrity signal is lost, If this happens, all the
watch dog signals go away, and the thermostat runs the ventilation directly. This
is the first level of backup protection. If any communication problem exists in the
system, an alarm is issued by the System Watch Dog Timer Unit, and sent
directly to an outside alarm system (the second level backup protection).