Day: August 21, 2026

Single inlet and double inlet centrifugal fan wheels compared
By longwell / August 21, 2026 / Fan Engineering Guides

Single Inlet vs Double Inlet Centrifugal Fans: What are different?

A double inlet wheel takes air from both sides, roughly doubling airfl...

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Manometer showing negative pressure difference across a doorway
By longwell / August 21, 2026 / Fan Engineering Guides

Positive vs Negative Pressure Ventilation

Room pressure decides which way air leaks through every gap in the bui...

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External rotor motor with the impeller mounted directly on the rotor
By longwell / August 21, 2026 / Fan Engineering Guides

External Rotor vs Internal Rotor Motor Fans

In an external rotor motor the outside spins and the impeller mounts s...

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Plenum fan mounted on a bulkhead inside an air handling unit
By longwell / August 21, 2026 / Fan Engineering Guides

Plenum (Plug) Fan vs Housed Fan for AHU

A plenum fan blows into the cabinet rather than into a scroll. That co...

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Multimeter used to measure a fan capacitor on the capacitance range
By longwell / August 21, 2026 / Fan Engineering Guides

How to Test a Fan Capacitor with a Multimeter

Testing a capacitor takes a minute once the safety steps are done prop...

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Wheel puller fitted to a stuck blower wheel on a motor shaft
By longwell / August 21, 2026 / Fan Engineering Guides

Removing a Stuck Blower Wheel (Puller Trick)

A hub that has spent years on a shaft in a damp cabinet does not come ...

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Technician testing an ECM module separately from the motor
By longwell / August 21, 2026 / Fan Engineering Guides

Bad ECM Module vs Bad Motor: How to Tell

ECM faults split three ways: the module, the motor or the system aroun...

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Furnace blower running continuously with control board access panel open
By longwell / August 21, 2026 / Fan Engineering Guides

Furnace Blower Won’t Turn Off — Fix

A blower that runs continuously is usually being told to, either by a ...

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Cleaning a mini-split blower wheel cross-flow drum inside the indoor unit
By longwell / August 21, 2026 / Fan Engineering Guides

Cleaning a Mini-Split Blower Wheel

The cross-flow drum inside a mini-split collects a film of dust and bi...

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RV roof fan motor being replaced inside a camper roof vent
By longwell / August 21, 2026 / Fan Engineering Guides

RV Roof Fan Motor Replacement

A roof vent fan that stops usually has a short list of causes, and the...

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