The Hartzell Blog

October 2026

Fan Vibration and Balance Why It Matters and What to Do When a Fan Starts to Shake

By David Long

Fan vibration is the earliest signal that something in a fan system is wrong, and it is also one of the most destructive forces acting on the equipment. Left unaddressed, it loosens fasteners, wears bearings, cracks welds, and turns down shafts. This guide covers what causes fan vibration, why balance matters, how it is measured and corrected, and what to do when a fan that ran smoothly starts to shake.

October 2026

Keeping Critical Spare Parts on the Shelf How It Protects Your Operation

By David Long

Why is keeping critical spare parts on the shelf important? When a belt breaks, a bearing starts to fail, or an impeller comes out of service, the repair itself is straightforward but the wait times are costly. The fan sits idle while the right part is identified, quoted, produced, and shipped. This guide covers how stocking spares protects your operation and how to decide which ones belong in your inventory.

September 2026

How to Read a Fan Curve From Duty Point to Installed Performance

By David Long

A published fan curve describes the fan under lab conditions, not your ductwork. Here's how to read one for what it actually tells you: where the duty point sits, what the fan laws do when speed or density changes, and the two things printed on every sheet that decide whether the curve applies to you.

September 2026

Spark-Resistant Blowers How to Specify the Right Construction for a Combustible Airstream

By David Long

When an airstream carries combustible dust or flammable vapor, the fan is often the one part fast enough to ignite it. Here's how to specify spark-resistant construction from the airstream up, including what changes when the fan is fiberglass and the AMCA types don't fit.