or heavy scaling

including the flame sensor and blocked drain switch

This air pressure switch serves as a primary limit to prevent ignition during blocked vent conditions or gas furnace venting failures

Designed for power-limited circuits

including various Discus models requiring capacity modulation

Williams P623677 Motor 321142-301 or heavy scalingThe Williams P623677 Motor is a precision engineered OEM replacement blower motor designed specifically for Williams Comfort Products heating systems. This heavy duty 1 8 HP motor operates on standard 115V single phase power, delivering a consistent 1550 RPM output across its 4 speed furnace motor configuration. Designed for high static pressure applications, this PSC motor ensures optimal airflow through the heat exchanger, maximizing heat transfer