Johnson Controls T-3111-2 Pneumatic Thermostat 30067439-890 it provides critical low water

it provides critical low water protection to prevent dry firing

Broad Compatibility: Fully compatible with Fenwal fire alarm smoke and heat detectors using 2-wire or 4-wire bases

Contractor-Grade Durability: Built to withstand extreme outdoor temperature fluctuations and moisture exposure

Corrosion Resistance: Heavy-duty galvanized construction resists flue gas moisture

Johnson Controls T-3111-2 Pneumatic Thermostat 30067439-890 it provides critical low waterPneumatic Thermostats and Valve Actuator, Reverse Acting, Remote Bulb, External Setpoint Adjustment, Valve Top Mounting, Single Temperature and Pressure This item is not qualified for free shipping.