The Johnson Controls T-4000-3141 is a commercial-grade pneumatic thermostat cover designed for horizontal mounting configurations within HVAC control systems

ensuring proper airflow monitoring and furnace sequencing

By replacing these worn components

For oil-related service

The F29-0231 fits most standard White-Rodgers horizontal thermostats

Trane CNT3520 Pressure Switch The Johnson Controls T-4000-3141 isThe Trane CNT3520 is a critical OEM HVAC pressure switch engineered for precise negative pressure detection in residential and commercial air handlers and furnaces. As a single pole double throw (SPDT) switch, this component provides versatile electrical control, allowing for normally open or normally closed circuit configurations depending on the sequence of operation. Calibrated to a fixed setpoint of 0. 15" WC (water column), the CNT3520 serves as