or if you measure an open circuit across the terminals when the furnace is cool

this blue adjustment spring allows for an outlet pressure range of 5 to 12 inches Water Column (WC)

Durable Construction: Forged from corrosion-resistant brass to withstand the rigors of commercial and industrial HVACR mechanical rooms

5" WC outlet pressure range

while the 237 Ohm resistor is connected across terminals B and R to facilitate the 4-20 mA signal conversion

Nordyne 624345R Outdoor Thermostat or if you measure anThe Nordyne 624345R Outdoor Thermostat is a critical field service component designed for precise ambient temperature sensing in split system heat pumps and cooling units. As a direct OEM 624345 replacement part, this heavy duty controls assembly ensures seamless integration into existing Nordyne HVAC systems, high efficiency Miller furnaces, and Intertherm mobile home equipment. Engineered for electrical reliability, this 24V outdoor thermostat