you can power the timing mechanism independently of the switched loads

or communication loss at the zone controller level

000 BTU/h (Option CA1)

this model is the direct technical successor to the legacy 0274547

Hydrotherm 59-1089 Air Filter 318518-761 you can power the timingThe Hydrotherm 59 1089 Combustion Air Filter is a critical OEM filtration component engineered to maintain the stoichiometric balance and internal cleanliness of high efficiency condensation and hydronic heating systems. Specifically designed as a direct replacement for Hydrotherm boilers, this combustion air filter intercepts airborne particulates, dust, and environmental debris before they can reach the burner assembly. By providing a consistent