Viessmann 7856004 Pump Head 322838-752 or diagnostic codes on the

or diagnostic codes on the boiler control board indicating ignition failure or lost flame signal

and XV18 series

Manual Reset Safety: Prevents uncontrolled restarts after safety circuit interruptions

Spring Return Failsafe: Ensures the damper returns to the start position during power interruptions

Smith 100172003 Gas Valve Assembly is a critical OEM component designed for high-efficiency negative pressure regulation in Knight KBN150 and AWN150 series boilers

Viessmann 7856004 Pump Head 322838-752 or diagnostic codes on theThe Viessmann 7856004 Pump Head is a precision engineered Grundfos UPS15 78 B1KA replacement designed for high head hydronic applications. This boiler circulation pump assembly is the OEM solution for restoring hydraulic balance in Viessmann Vitodens 100 W and 200 series condensing boilers. Featuring a 3 speed motor configuration, this wet rotor circulator allows for fine tuning the flow rate to match the specific friction loss of the heat exchanger