The Belimo Actuator Mounting Methods Guide is the industry standard for getting these installations right, but interpreting it on the fly can be a headache. That’s where we come in. At Boston Aircontrols, we are a family-owned operation and the #1 Belimo Platinum Distributor in New England. We know this hardware inside and out.
To save you time and prevent unnecessary callbacks, we’ve broken down the core principles from Belimo’s official guide into this quick, job-site-ready cheat sheet.
1. The Standard: Direct-Coupled Mounting
Belimo revolutionized the HVAC controls industry with the direct-coupled actuator. By clamping directly onto the damper shaft, you make actuation the simplest and most reliable method to control airflow, eliminating the sloppy linkages that cause “deadband”.
- The Universal Clamp: Belimo’s unique open-ended universal clamp (like the ZG-JSL linkage) is designed to facilitate the attachment of select Belimo actuators to a damper’s jackshaft. The design allows the linkage to clamp onto any part of a jackshaft measuring from ½” to 1.05” in diameter.
- The Rule of Alignment: It is imperative that trade best practices are upheld to ensure connecting components and bracketing remain straight and true. The actuator base should always be parallel to the mounting surface.
2. The Anti-Rotation Strap: Let It Float!
If there is one technical failure we see time and time again, it’s a rigidly bolted anti-rotation strap.
When you install the anti-rotation bracket, it must allow for some actuator “float” or play. The anti-rotation pin is to be centered in the anti-rotation slot. The pin should never be buried into the slot, preventing movement, or failure can occur. Let it breathe!
3. The Short Shaft Solution
We’ve all been there: the damper OEM didn’t leave you enough shaft length to grab onto with a standard mount.
Instead of fabricating a nightmare of crank arms, simply move the clamp. The universal mounting clamp is most often mounted on the front of the actuator body, but it can be installed on the back for short shaft installations. Just ensure you position the clamp to allow access to the nuts for tightening.
4. High-Torque on Large Dampers and Jackshafts
When you are dealing with massive, multi-section damper assemblies, throwing the largest actuator possible on one side of a long jackshaft is a recipe for disaster.
- Split the Load: For multiple dampers directly connected to one actuator, torque distribution is optimized when the crank arm is positioned between the dampers.
- Hollow Jackshafts: If the jackshaft diameter is larger than the actuator will accept, use either EMT tubing or a JSA shaft adapter. A less time-consuming method preferred by installers is to use the ZG-JSA-1, ZG-JSA-2, or ZG-JSA-3 jackshaft adapter, which is designed to be inserted into hollow jackshafts. Placed into the jackshaft, you tighten the tension nut to expand against the inner shaft.
BAC Pro-Tip:
If you are working with hollow jackshafts, ditch the through-bolts. Use ZG-JSA jackshaft adapters, which expand against the inner walls of the shaft for a perfectly centered, slip-free grip.
5. Non-Direct Coupled (Linkage) Applications
Sometimes, direct coupling just isn’t physically possible. In these cases, you’ll need to utilize crank arms and push rods (like the KH6 or KH8 crank arms).
When building a mechanical linkage, the golden rule of geometry applies: The push rod and crank arms should be set up so the crank arms on both the actuator and damper rotate 45° from a line perpendicular from the rod to the center of the crank arm rotation. This provides a balanced torque load to the damper and minimizes any chance of the linkage binding.
Stop Troubleshooting and Start Installing with Confidence
A Belimo actuator is the most reliable motor in the industry, but its performance is only as good as the geometry behind it. Whether you’re reversing a clamp for a tight-clearance fix or syncing primary/secondary units for a high-torque damper, the technical details are what separate a set-it-and-forget-it install from a costly callback.
At Boston Aircontrols, we’ve spent more than 25 years as the technical backbone for New England’s mechanical contractors. We don’t just ship boxes; we provide the field-tested expertise and local support you need to keep your projects on track, on budget, and running at peak performance.
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