Symptom - Falling Effectiveness

• Cause: fouling or airstream leakage
• Fix: clean the core; reseal interfaces; verify duct connections

Symptom - Rising Pressure Drop

• Cause: dust, grease, or frost buildup
• Fix: clean the core; check frost strategy in winter

Symptom - Frost on Core

• Cause: defrost not triggering or set too high
• Fix: lower the defrost setpoint; confirm preheat or bypass works

Symptom - Wheel Noise or Vibration

• Cause: belt, bearing, or seal wear
• Fix: inspect and replace per schedule; re-balance the wheel

Symptom - High Humidity Indoors

• Cause: enthalpy wheel or membrane under-performing
• Fix: verify latent rating; check media condition; confirm rotation