Floating Point · 3-Wire · No Spring Return
HAC-30
HAC-30
Belimo LMB24-3-T
Inline Damper
3-Wire Open / Stop / Close · 24 Vac/dc · Lighter-Duty Floating Point · 6"–20"
- ✓3-wire floating point — Open / Stop / Close incremental positioning
- ✓No spring return — holds last blade position on power loss
- ✓24 Vac or 24 Vdc supply voltage
- ✓Lower torque class — suited to smaller and mid-range duct sizes
- ✓End switch available on all sizes for BAS position confirmation
- ✓Heat bypass (−H) available on all sizes
- ✓Factory-mounted Belimo LMB24-3-T — ships ready to install
Is this the right product?
✔ Right product if
Your DDC controller has a 3-wire floating point output (Open / Stop / Close), the spec is actuator-neutral or specifically calls for LMB24-3-T, and the lower torque class suits the duct size and static pressure.
✗ Not this product if
Spec calls for CMB24-3-T → use HAC-34 — higher torque, same architecture.
Spring return fail-safe required → use HAC-40 (TFB24)
Analog 2–10 VDC control → use HAC-43 or HAC-60
Spring return fail-safe required → use HAC-40 (TFB24)
Analog 2–10 VDC control → use HAC-43 or HAC-60
What It Does
3-wire Open / Stop / Close. DDC floating point output. Lighter-duty companion to the HAC-34. Holds last position on power loss.
NO SPRING RETURN — Blade Holds Last Position on Power Loss
The LMB24-3-T has no spring return. On power loss the blade stays wherever it was — it does not move to a defined open or closed fail-safe position. If your application requires the damper to seal or open on power loss, use a spring return product: HAC-40 (TFB24) for on/off, or HAC-43 (TFB24-SR-T) for modulating.
The HAC-30 pairs Hoyme's inline damper body with the Belimo LMB24-3-T — the lighter-duty version of the CMB24-3-T used in the HAC-34. Same Open / Stop / Close 3-wire control architecture. Same holds-last-position behavior on power loss. The practical distinction is torque: the LMB24-3-T is suited to smaller and mid-range duct sizes where the CMB's higher torque is not required. When the specification is actuator-neutral, select based on duct size and static pressure. When the specification names LMB24-3-T, this is the product.
3-Wire Control — How It Works
OPEN
Energized → blade moves toward open while wire is energized
CLOSE
Energized → blade moves toward closed while wire is energized
STOP
Neither energized → blade holds current position
LMB vs. CMB — torque is the only difference: If the spec names CMB24-3-T, order the HAC-34. If the spec is actuator-neutral, the LMB is appropriate for smaller and mid-range sizes at moderate static pressure. The CMB is the safer choice for larger sizes, higher static pressure, or when in doubt — over-torquing a damper blade causes no harm; under-torquing can result in incomplete blade travel.
LMB24-3-T vs. CMB24-3-T — The One Practical Difference
Same 3-wire floating point architecture. Same holds-last-position behavior. Torque class is the only meaningful distinction.
| Spec | HAC-30 (LMB24-3-T) — this product | HAC-34 (CMB24-3-T) |
|---|---|---|
| Control Architecture | 3-wire floating point | 3-wire floating point |
| Supply Voltage | 24 Vac/dc | 24 Vac/dc |
| On Power Loss | Holds last position | Holds last position |
| Torque Class | Lower — smaller/mid-range sizes | Higher — larger sizes, higher static pressure |
| Heat Bypass (−H) | Available | Available |
| End Switch | Available | Available |
| Best For | Actuator-neutral specs; smaller/mid-range sizes at moderate static pressure | Specs calling for CMB24-3-T; larger sizes; higher static pressure |
Belimo Series — Control Type Selector
All Belimo-actuated HAC variants on a single Hoyme inline damper body. Select by control type and voltage.
| Model | Actuator | Control Type | Voltage | Spring Return | Link |
|---|---|---|---|---|---|
| HAC-40 | TFB24 | On/Off | 24 Vac/dc | Yes | View |
| HAC-44 | TFB120 | On/Off | 100–240 Vac | Yes | View |
| HAC-43 | TFB24-SR-T | Modulating 2–10 VDC | 24 Vac/dc | Yes | View |
| HAC-60 | LMB24-SR-T | Modulating 2–10 VDC | 24 Vac/dc | No — holds last | View |
| HAC-34 | CMB24-3-T | Floating point 3-wire | 24 Vac/dc | No — holds last | View |
| HAC-30 ← You are here | LMB24-3-T | Floating point 3-wire | 24 Vac/dc | No — holds last | — |
| HAC-35 | CMB120-3 | Floating point 3-wire | 100–230 Vac | No — holds last | View |
| HAC-70 | LMX120-3 | Floating point 3-wire | 100–230 Vac | No — holds last | View |
| HAC-90 | FSLF24 US | Fire & Smoke (UL 555S) | 24 Vac | Yes | View |
| HAC-80 | FSLF120 US | Fire & Smoke (UL 555S) | 120 Vac | Yes | View |
Configuration Guide
Select size, end switch, and heat bypass. Confirm 3-wire terminal assignments with the DDC controls designer before wiring.
| Variant Code | End Switch | Heat Bypass | Part Number Example (10") |
|---|---|---|---|
| OPP | No end switch | No bypass | HAC-1030-OPP |
| OPP-H | No end switch | 10% bypass | HAC-1030-OPP-H |
| SPP | End switch included | No bypass | HAC-1030-SPP |
| SPP-H | End switch included | 10% bypass | HAC-1030-SPP-H |
−H Heat Bypass — Hot Air Zone Control Only: Do not specify −H on fresh air intake, make-up air, or ventilation applications. The 10% bypass allows continuous outdoor air infiltration when the damper is at minimum position. Specify −H only on hot air supply duct zone control applications.
Part Number Decoder
HAC-1430-SPP
HAC
Product family: universal inline air control damper
14
Size (2-digit): 06=6", 08=8", 10=10", 12=12", 14=14", 16=16", 18=18", 20=20"
30
Motor code: Belimo LMB24-3-T, 3-wire floating point, 24 Vac/dc, no spring return
O / S
End switch: O = no end switch | S = end switch included
PP
Floating point action code for LMB24-3-T 3-wire architecture
-H
Optional: 10% heat bypass. Hot air zone control only.
Key Specs
Sizes
6", 8", 10", 12", 14", 16", 18", 20"
Actuator
Belimo LMB24-3-T
Control Wires
3-wire: Open / Stop / Close
Supply Voltage
24 Vac or 24 Vdc
Fail-Safe
Holds last position — no spring return
Torque Class
Lower — confirm for duct size & static pressure
End Switch
Optional (S prefix)
Heat Bypass
Optional (−H suffix)
Relay
Not available
CSA Status
Confirm with Hoyme
Warranty
2-yr electrical / 10-yr mechanical
Common Questions from the Counter
Answers to what comes up most when specifying the HAC-30.
When should I use the LMB24-3-T (HAC-30) instead of the CMB24-3-T (HAC-34)?
When the project specification is actuator-neutral and the LMB's lower torque class is adequate for the duct size and static pressure. The LMB is appropriate for smaller and mid-range sizes at moderate static pressure. The CMB is the safer choice for larger sizes, higher static pressure applications, or when the spec specifically names CMB24-3-T. If in doubt, specify the CMB (HAC-34) — over-torquing a damper blade causes no harm; under-torquing can result in incomplete blade travel or missed position stops.
What happens to the blade on power loss?
The blade holds its last position. The LMB24-3-T has no spring return. If the system was running at 60% open when power went out, the blade stays at 60% open until power restores and the DDC controller sends a positioning command. If the application requires the blade to move to a defined position on power loss, use a spring return product: HAC-40 (TFB24) for on/off or HAC-43 (TFB24-SR-T) for modulating.
How do I know if my DDC card has floating point outputs?
Check the DDC output card specification for terminal pairs labeled Open/Close, CW/CCW, or similar. Floating point cards pulse these terminals to position the actuator incrementally. If the card outputs a continuous 0–10 VDC analog signal instead, use the HAC-60 (LMB24-SR-T modulating). If the card has a simple switched output, use the HAC-40 (TFB24 on/off).
Is the heat bypass available on the HAC-30?
Yes — the −H suffix is available on all HAC-30 sizes. Specify −H only on hot air supply duct zone control applications where full closure causes heat buildup on a single-speed furnace. Do not specify −H on fresh air or ventilation applications — the bypass allows continuous air movement when the damper is at minimum position.
Ready to Order
HAC-30 — Belimo LMB24-3-T Inline Damper
Select your size, end switch (OPP/SPP), and heat bypass option — then add to cart.
Configure & Order →
Size · End Switch · Heat Bypass
Need help specifying the HAC-30?
Technical support available through your Hoyme wholesaler or direct.