Modulating · 2–10 VDC · No Spring Return
HAC-60
HAC-60
Belimo LMB24-SR-T
Inline Damper
Proportional Blade Positioning · 24 Vac/dc · Holds Last Position · 6"–20"
✓
2–10 VDC analog input — proportional blade positioning from 0 to 100% open
✓
No spring return — holds last blade position on power loss
✓
24 Vac or 24 Vdc supply voltage
✓
OPP (no end switch) or SPP (end switch included) — confirm configuration with engineer before ordering
✓
Heat bypass (−H) available on all sizes
✓
Factory-mounted Belimo LMB24-SR-T — ships ready to install
Is this the right product?
✔ Right product if
Your BAS or DDC controller outputs a 2–10 VDC analog signal for proportional damper positioning, and holding last position on power loss is acceptable for your application.
✗ Not this product if
Spring return fail-safe required → use HAC-43 (TFB24-SR-T) — same 2–10 VDC modulating control with spring return.
3-wire floating point → HAC-34 (CMB24-3-T)
On/off 2-position → HAC-40 (TFB24)
3-wire floating point → HAC-34 (CMB24-3-T)
On/off 2-position → HAC-40 (TFB24)
What It Does
Proportional 2–10 VDC modulating control. No spring return — holds last position on power loss.
NO SPRING RETURN — Blade Holds Last Position on Power Loss
On power loss, the HAC-60 blade holds wherever it was. It does not move to a defined open or closed fail-safe position. If your application requires the damper to move to a defined position on power loss, use the HAC-43 (Belimo TFB24-SR-T), which provides the same 2–10 VDC modulating control with spring return fail-safe.
The HAC-60 pairs Hoyme's inline damper body with the Belimo LMB24-SR-T modulating actuator. Like the HAC-43 (TFB24-SR-T), the LMB24-SR-T accepts a 2–10 VDC analog signal and positions the damper blade proportionally across the full range of travel. The single practical difference: the LMB24-SR-T has no spring return. On power loss, the blade holds its current position rather than moving to a defined fail-safe open or closed state.
For most commercial BAS applications where the DDC controller manages blade position and resumes control after a power event, holds-last-position is the preferred behavior — it avoids abrupt airflow changes during brief power interruptions. Where a defined fail-safe position is required, use the HAC-43.
HAC-60 vs. HAC-43 — The One Decision That Matters
Both accept 2–10 VDC and provide proportional blade positioning. The only meaningful difference is how they behave on power loss.
| Spec | HAC-43 (TFB24-SR-T) | HAC-60 (LMB24-SR-T) — this product |
|---|---|---|
| Control Input | 2–10 VDC analog | 2–10 VDC analog |
| Proportional Range | Full blade travel | Full blade travel |
| Supply Voltage | 24 Vac/dc | 24 Vac/dc |
| On Power Loss | Spring return to fail-safe position (open or closed) | Holds last blade position — no movement |
| Heat Bypass (−H) | Not available | Available on all sizes |
| Choose When | Fail-safe position required on power loss | Holds-last-position is acceptable; lighter actuator suits the application |
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 ← You are here | LMB24-SR-T | Modulating 2–10 VDC | 24 Vac/dc | No — holds last | — |
| HAC-34 | CMB24-3-T | Floating point 3-wire | 24 Vac/dc | No — holds last | View |
| HAC-30 | LMB24-3-T | Floating point 3-wire | 24 Vac/dc | No — holds last | View |
| 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 (OPP or SPP), and heat bypass. Confirm PP action code signal direction with the DDC controls designer before ordering.
| Variant Code | End Switch | Heat Bypass | Part Number Example (10") |
|---|---|---|---|
| OPP | No end switch | No bypass | HAC-1060-OPP |
| OPP-H | No end switch | 10% bypass | HAC-1060-OPP-H |
| SPP | End switch included | No bypass | HAC-1060-SPP |
| SPP-H | End switch included | 10% bypass | HAC-1060-SPP-H |
PP Action Code — Confirm Signal Direction Before Ordering: The PP code encodes the signal direction configuration for the LMB24-SR-T. Whether increasing VDC opens or closes the blade must match the BAS control sequence. Confirm the required signal direction with the mechanical engineer or DDC controls designer before ordering.
−H Heat Bypass — Hot Air Zone Control Only: The −H bypass is permanent and cannot be disabled. Do not specify −H on fresh air intake, make-up air, or ventilation applications — the 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-1460-SPP-H
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"
60
Motor code: Belimo LMB24-SR-T, modulating, 24 Vac/dc, no spring return
O / S
End switch: O = no end switch (OPP) | S = end switch included (SPP)
PP
Modulating action code for LMB24-SR-T — confirm signal direction with controls designer
-H
Optional: 10% heat bypass machined into blade. Hot air zone control only.
Key Specs
Sizes
6", 8", 10", 12", 14", 16", 18", 20"
Actuator
Belimo LMB24-SR-T
Control Input
2–10 VDC analog
Supply Voltage
24 Vac or 24 Vdc
Fail-Safe
Holds last position — no spring return
End Switch
Optional — S prefix (SPP/SPP-H)
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-60.
What's the practical difference between the HAC-60 (LMB24-SR-T) and the HAC-43 (TFB24-SR-T)?
Both accept 2–10 VDC and position the blade proportionally. The TFB24-SR-T (HAC-43) has spring return — on power loss it moves the blade to a defined fail-safe position (open or closed). The LMB24-SR-T (HAC-60) holds last position on power loss — no movement. On most commercial BAS installations where the DDC controller resumes control after a power event, holding last position is the preferred behavior. Where a defined fail-safe position is required, use the HAC-43.
What happens to blade position on a brief power interruption?
The blade holds wherever it was when power went out. On power restoration, the BAS resumes control and repositions the blade as required by the control sequence. On most systems this is the correct behavior — a spring return movement on every brief power interruption would cause airflow disruption that's harder to recover from than simply holding position through the event.
Is there an end switch option on the HAC-60?
Yes — the end switch is included in the SPP and SPP-H variants. The S prefix indicates end switch included; the O prefix (OPP/OPP-H) is the no-end-switch variant. If position feedback to the BAS is required, order the SPP (end switch, no bypass) or SPP-H (end switch, heat bypass) variant.
Is the heat bypass (−H) available on the HAC-60?
Yes — the −H suffix is available on all HAC-60 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.
Do I need modulating control, or will on/off work?
On/off works for the majority of fresh air damper applications — open when called, closed when not. Modulating is required when the control strategy demands proportional positioning: demand-controlled ventilation, mixed air temperature control, building pressure management, VAV fresh air tracking. If the system doesn't require any of those strategies, use the HAC-40 (TFB24 on/off) — less expensive, simpler to wire, and provides spring return fail-safe.
Ready to Order
HAC-60 — Belimo LMB24-SR-T Inline Damper
Select your size, variant (OPP/SPP), and heat bypass option — then add to cart.
Configure & Order →
Size · End Switch · Heat Bypass
Need help specifying the HAC-60?
Technical support available through your Hoyme wholesaler or direct.