Solving balancing challenges in Compact air handlers (AHUs)
In our recent site inspection, a seemingly “healthy” AHU turned out to have multiple hidden issues—each capable of triggering unwanted vibration, excessive noise, and premature wear. What started as a quick visual check ended with a list of critical corrective actions.
Key factors that make balancing critical
- Motor capacity: Usually below 10 HP, but even small imbalance has noticeable effects.
- Drive system: Belt-driven or direct-drive fan wall units, each with unique balancing needs.
- Mounting method: Commonly installed on spring isolators to reduce vibration transfer.
- Speed variation: Modern VFDs allow a wide speed range, increasing the risk of resonance.
Let’s break down the common causes of fan vibration in compact AHUs and how to fix them—and what to do before jumping into balancing.
The result: Simpler balancing, smoother operation
In the site example mentioned earlier, just a few proactive fixes—cleaning, rust removal, isolator tuning, and proper sheave alignment—helped reduce vibration significantly. The fan didn’t even need rebalancing afterward.
Moral of the story?
Before reaching for a balancing tool, ensure your basics are covered. Most vibration issues aren’t caused by imbalance alone—they’re symptoms of overlooked mechanical or installation errors.
When balancing is needed—make it smart
Once all the fundamentals are addressed, if balancing is still necessary, you’ll be working with a well-prepared system—making the job quicker, easier, and more effective.
For precision balancing, consider the Acoem Wireless Balancer—the industry’s first wireless, two-plane synchronous balancing tool that delivers accurate results with real-time data and zero cable clutter. It’s compact, powerful, and built for the kinds of machines that often get ignored… until it’s too late.
Don’t let a small fan become a big problem.
