the MARS 11953 is the likely solution

The Schneider Electric (Erie) VM3221 Valve Body is a robust 3-way mixing assembly engineered for precision in hydronic HVAC systems

Common indicators include the pump failing to engage during a call for heat

or differential pressure sensing without the need for additional bulky hardware

Technicians should measure the DC microamp signal in series with the flame sensor

White-Rodgers 36C53-418 Gas Valve R-410A the MARS 11953 is theThe White Rodgers 36C53 418 is a professional grade, 24V standing pilot gas valve designed for versatility in residential and light commercial heating applications. This slow open gas valve provides a 3 4" x 3 4" NPT connection and a robust capacity of 335,000 BTU hr (Natural Gas at 1" PD), making it an ideal choice for high demand furnaces and boilers. The slow opening feature ensures a controlled ignition sequence, reducing burner noise and