Description
Product image is representative only. Actual product may differ in appearance depending on size, configuration, and options selected at order.
Hoyme inline damper body with Belimo FSLF24 US — a UL 555S listed fire and smoke actuator for smoke damper applications at 24 Vac. The FSLF designation is not a marketing label. It means the actuator has been tested and listed to UL Standard 555S — covering minimum torque, maximum actuation time to fail-safe, elevated temperature performance, and construction for smoke-laden air. Sizes 6"–20".
⚠ Do Not Substitute HAC-40 (TFB24) on Smoke Damper Applications
The standard Belimo TFB24 (HAC-40) is NOT UL 555S listed and does not meet the torque, actuation speed, elevated temperature, or construction requirements for smoke damper service. Substituting HAC-40 for HAC-90 on a code-required smoke damper application will not pass inspection, creates liability exposure for the installing contractor and building owner, and may affect the certificate of occupancy. The cost of replacement after a failed inspection exceeds the price premium of specifying HAC-90 correctly the first time.
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UL 555S listed — FSLF24 US — tested to the UL standard for smoke damper actuators: minimum torque, maximum time-to-fail-safe, elevated temperature performance, smoke-laden air construction
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24 Vac/dc supply — receives fail-safe signal from smoke control panel; coordinates with fire alarm system and smoke control commissioning sequence
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End switch available on all sizes — provides position feedback to the fire alarm or smoke control system; wiring requirements specified by smoke control system design, not HVAC contractor preference
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Belimo FSLF24 US field-replaceable — available through Belimo distributors; after replacement, smoke damper system must be re-commissioned and replacement documented per maintenance requirements
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120 Vac smoke damper application? — see HAC-80 (FSLF120 US) — same UL 555S listing, line voltage supply
Action code must be confirmed by the fire protection engineer in writing before ordering. PO or PC on a smoke damper is a life-safety decision that determines which position the blade moves to during a fire event. Different locations in the same smoke control system may require different action codes. Do not assume, do not default — get the action code from the fire protection engineer before placing the order.
HAC-90 (FSLF24 US) — smoke damper
✓UL 555S listed — smoke damper actuator standard
✓Elevated temperature performance — tested for fire event conditions
✓Maximum actuation time to fail-safe — meets UL 555S timing requirement
✓Required on smoke dampers — code, specification, or AHJ mandates UL 555S
HAC-40 (TFB24) — standard HVAC only
→Not UL 555S listed — not acceptable for smoke damper applications
→Standard HVAC temperature range only
→Fresh air, ventilation, zone control — no listing requirement
→Lower cost — correct choice when UL 555S is not required
Listing
UL 555S — smoke damper actuator
Actuator
Belimo FSLF24 US
Supply Voltage
24 Vac/dc
Sizes
6"–20" even inches
Action Code
Fire protection engineer — in writing
TFB24 Substitute?
Never — not listed for smoke service
Smoke control system coordination required. The HAC-90 does not operate independently. The FSLF24 US receives its fail-safe signal from the smoke control panel — not from a standard HVAC controller or BAS. Coordinate with the fire protection engineer and fire alarm system installer on control wiring, fail-safe signal source, and the verification sequence required by the smoke control commissioning plan. End switch wiring requirements are specified by the smoke control system design. For 120 Vac smoke damper applications see HAC-80 (FSLF120 US).
2-year electrical · 10-year mechanical warranty
Hoyme damper body — Made in Canada · Belimo FSLF24 US field-replaceable through Belimo distributors