R-ProField casesRefrigeration systems

Evaporative Drain Fan Failure

Likely causes

Fan motor coil break or burnout

Check: Measure fan motor coil resistance — break: ∞; insulation resistance below 1MΩ = burned; check manual rotation

What to do: Replace with same spec fan motor; verify drain fan operates normally after replacement

Capacitor failure — startup impossible

Check: Measure capacitor capacitance — normal within ±10% of rated; manually rotates but won't start = capacitor failure

What to do: Replace with same capacitance capacitor; verify normal with startup current measurement after replacement

Float switch failure — water level control malfunction

Check: Verify float switch operation — normal: fan stops when water rises, starts when water drops; switch seized or malfunctioning = overflow or dry running

What to do: Clean or replace float switch; remove scale from basin via cleaning; verify water level control operation after replacement

Field tip

Evaporative drain fan and float switch are one system — first distinguish whether it's fan failure or float switch failure; whether motor rotates manually distinguishes coil vs capacitor issue

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