White-Rodgers F29-0231 Plastic Guard The Johnson Controls T-4000-2138 is

The Johnson Controls T-4000-2138 is a professional-grade beige plastic thermostat cover designed specifically for T-4000 series pneumatic room thermostats

PTFE seats

Thermal Resiliency: Rated for high-temperature environments up to 180

allowing for a secure "plug-and-play" interface with Copeland Comfort Control (Alco) Controls hardware

replacing a pitted or oxidized sensor with a fresh OEM rod ensures the system maintains proper HVAC flame monitoring and operational safety

White-Rodgers F29-0231 Plastic Guard The Johnson Controls T-4000-2138 isThe White Rodgers F29 0231 is a professional grade clear plastic thermostat guard designed to eliminate unauthorized adjustments and protect sensitive climate controls in high traffic environments like offices, churches, and rental properties. This model features a dual mounting configuration, including both a ring base and a solid wall mounting plate, providing maximum versatility for field installations. Built with high impact polycarbonate, this