LEFOO LF55T Capillary Temperature Control and Frost Switch
LEFOO LF55T is a capillary frost protection temperature switch for bulb temperature (not pressure). The distinction between a flow, pressure, temperature, protective or remote-actuator contact matters when selecting replacements.
Model Identification & Key Specifications
Original Manufacturer Data
LF55T is a THERMOSTAT, not an LF55 pressure switch. Capillary vapour charge option has small differential and adsorption charge supports frost protection. OEM standard cold range −30…15°C, 2–10°C differential, setpoint −7/−9°C, alternative −5…30°C 2–10°C differential. Critical contact wiring: terminals 1–4 for LOW temperature protection and 1–2 for HIGH temperature protection. Bare IP30 versus IP44 with cover/bracket, process −40…120°C, ambient −25…65°C; active sensing length at least 0.43m capillary by maker.
Confirm the manufacturer original model/order suffix, correct operating medium and mounting, switched load and power supply, safety device architecture, verified original maker photograph and applicable current approval documentation. Use the latest model-specific manufacturer technical references and correct photographs.
AirAlign Engineering & Variant Comparison
LF55T is not an LF55 refrigerant pressure switch. The capillary’s active sensing length, mounting and vapor/adsorption charge option determine trip response. Bare IP30 differs from the IP44 enclosure arrangement with cover; do not promise one protection level for all assemblies.
Always identify whether the part measures a continuously variable signal, provides a discrete protective trip or controls an operating cycle. Component substitution should preserve sensing topology, switching hysteresis, reset and energized/deenergized states. Enclosure and cable routing must be assessed within the actual equipment, not only against a standalone catalogue illustration.
Installation and Integration Checks
Check supply voltage, relay versus transistor wiring, contact NO/NC state and peak inductive duty. Signal outputs are not equivalent to motor-control contacts.
Distinguish temperature difference from independent thermal limits, and paddle/piston/calorimetric flow measurement from pressure differential. Match actual calibration media.
Mount as specified for the device’s reference sensor or mechanical paddle; verify working medium, housing, ingress protection, maximum process temperature and cable/port fittings.
Confirm applicable safety function and approvals for the exact order-code revision. Match any applicable CE, UL or TÜV documentation to the exact device configuration.
Related Products
LEFOO TS · LEFOO TSD · LEFOO manufacturer profile
Official Manufacturer Sources
Independent AirAlign engineering page. Device-specific maker photo and current exact-variant third-party approvals require separate verification.
LF55T — capillary frost stat sensing path
LF55T is a capillary temperature/frost protection switch, not a pressure switch. Its sensing bulb/capillary must be routed according to the relevant coil/duct exposure so an approaching freezing condition produces the required protective contact. Distinguish the configured low-temperature switching point from capillary or electronics maximum temperature. Verify reset type and fan/valve interlock action as part of the air-handler sequence rather than using the contact as a continuous temperature measurement.