replacing the 100077874 assembly often resolves the issue provided the gas valve and control board are functional

this model is specifically engineered for water-based media including chilled and hot water up to 250°F

Check for a restricted capillary tube

also used across several State

Is the discharge pipe size important

Laars Heating Systems RTXD7109 Replace Kit 318423-701 replacing the 100077874 assembly oftenThe Laars Heating Systems RTXD7109 Replace Kit is a direct OEM solution for restoring the Neotherm Wave 3 4A control architecture. Engineered for high efficiency condensing boilers and volume water heaters, this Neotherm Module Replace Kit serves as the central processing unit for system modulation and safety logic. As a veteran grade HVAC replacement part, it handles critical functions including integrated PID temperature control, direct spark