Description
The Siemens Building Technology 134-1511 is a single pole double throw (SPDT) freezestat engineered to provide dependable freeze protection in commercial HVAC air handling and ventilation systems. Featuring a manual reset (MR) mechanism, this control requires deliberate operator intervention before the system can be restarted after a freeze condition is detected — preventing repeated cycling and potential equipment damage.
The 134-1511 uses a 20-foot by 1/8-inch capillary sensing element that averages temperature across the full length of the tube, ensuring comprehensive coverage of large coil faces and duct cross-sections. When any portion of the capillary senses a temperature at or below the 35°F trip point, the SPDT contacts actuate to shut down the air handling unit or activate protective sequences. The control does not automatically reset until temperatures rise to approximately 45°F and the manual reset button is engaged.
Key Features
- SPDT (Single Pole Double Throw) switching action for versatile circuit control
- Manual Reset (MR) — prevents automatic restart after freeze event
- Trip setpoint: 35°F (1.7°C) for reliable freeze detection
- Reset point: 45°F (7.2°C) manual reset required
- 20-foot capillary tube for wide-area averaging temperature sensing
- 1/8″ capillary diameter for easy routing and installation
- Designed for AHU coil freeze protection in commercial HVAC applications
Typical Applications
- Air handling unit (AHU) freeze protection
- Heating and cooling coil low-temperature lockout
- Commercial ventilation system freeze safeguard
- Building automation and DDC system integration
Product Specifications
- SKU: 134-1511
- Brand: Siemens Building Technology
- Switch Type: SPDT
- Reset Type: Manual Reset (MR)
- Trip Temperature: 35°F
- Reset Temperature: 45°F
- Capillary Length: 20 feet
- Capillary Diameter: 1/8″
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