Johnson Controls A11A-1 Freezestat

The Johnson Controls A11A-1 is a robust low temperature cutout freezestat designed to provide failsafe protection for hydronic coils, cooling coils, and liquid handling pipes. Featuring a manual reset mechanism, this SPST open low control ensures that systems remain offline following a low-limit event until a technician can verify field conditions. The unit utilizes a 20-foot vapor-charged sensing element that triggers the internal snap-acting contacts when any 16 to 18-inch section of the capillary reaches the setpoint, regardless of the ambient temperature at the 4-foot capillary lead or the diaphragm cup.

Built for the rigors of commercial HVACR applications, the A11A-1 supports a broad voltage range from 24Vac to 277Vac. The 35 to 45 degree F cutout range and 12-degree fixed differential provide precise calibration through a direct-reading scale accessible via a screwdriver slot at the top or bottom of the case. For contractors installing in high-airflow environments, this freezestat offers the repeat accuracy necessary to prevent coil ruptures and costly flood damage while maintaining a dust-protected, galvanized steel enclosure for long-term reliability.

• Coldest Point Sensing: Responds to a localized 16" drop in temperature anywhere along the 20' element, preventing freeze-up in stratified air.
• Fail-Safe Trip-Free Reset: The manual reset lever cannot be bypassed or blocked; it must be manually cycled after the temperature rises 12°F above the setpoint.
• Universal Compatibility: Multi-voltage SPST switch action (24-277Vac) simplifies truck stock by replacing various fixed-voltage models.
• Installation Flexibility: Includes standard mounting brackets and features dual-access adjustment points for tight mechanical spaces.
• Heavy-Duty Construction: Features a galvanized steel case and precision snap-acting contacts to ensure a high pilot duty rating of 125 VA.

How do I reset the A11A-1 after a trip?
The temperature must rise at least 12°F above your cutout setpoint before the manual reset lever can be engaged. Simply press and release the lever to restore the circuit.

Where should the 20' sensing element be mounted?
It should be serpentine-mounted across the downstream face of the coil. Ensure that at least 16-18 inches are exposed to the coldest potential air pockets, typically at the bottom of the duct.

Can the control head be mounted in a different temperature zone?
Yes. The A11A-1 design ensures the sensing occurs only at the 20' bulb; the 4' capillary and the control diaphragm are ambient-compensated to prevent nuisance tripping.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.