The "Hold Open" switch allows the technician to keep the damper open during maintenance or startup without the burner being energized

protecting the heat exchanger from overheating and preventing carbon monoxide fallback into the residential space

including models like NAC036AKC3 and NAC042AKC3

Can the actuator be replaced without disconnecting the valve body

Includes a durable forged brass stem and ergonomic isolation handle for reliable manual flow control

Tekmar Controls 302P Switching Relay 319852-301 The "Hold Open" switch allowsThe Tekmar 302P Switching Relay is a professional grade solution for managing 2 zone hydronic heating systems with integrated priority logic. Designed for heavy duty commercial and residential applications, this unit allows a technician to connect up to two 24V (ac) thermostats to control two 115V (ac) circulator pumps. The microprocessor control provides a RoomResponse signal to optimize modulating condensing boiler efficiency by communicating real