Aging Room Humidity Control Failure (Unable to Maintain 85~95%RH)

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Accepted Answer

Humidifier nozzle clogged with lime scale — blocks within 2 weeks when water hardness exceeds 180ppm. Check: Visually check humidifier spray output — if below 50% of normal, nozzle clogged. Measure water hardness on-site What to do: 1. Disassemble nozzle and soak in 10% citric acid for 30 minutes
2. Recommend installing water softener (target hardness below 50ppm)
3. Cleaning interval: below 100ppm → monthly; 100~180ppm → every 2 weeks Humidity sensor contaminated or calibration error — actual vs displayed humidity differs by 5%RH+. Check: Insert sensor into a sealed container with saturated NaCl solution (75%RH reference) → if displayed value is outside 75±3%RH, calibration needed What to do: 1. Clean sensor exterior (dry cloth or compressed air)
2. Perform on-site calibration with saturated salt solution reference
3. Establish 90-day recalibration schedule Excessive ventilation drawing in dry air — ventilation rate above design (over 0.5 ACH). Check: Check ventilation timer settings + measure humidity drop rate during humidification operation (if humidity drops 5%RH/10min even with humidifier running, over-ventilation) What to do: 1. Interlock ventilation to stop during humidification
2. Concentrate ventilation during night hours (when no product loading/unloading)
3. Set minimum damper opening (limit to design ventilation volume) Cooling coil too cold causing over-humidification then condensation — coil surface below dew point. Check: Measure coil surface temperature + calculate dew point (from indoor temp/humidity) → condensation occurs if coil surface < dew point What to do: 1. Raise cooling coil set temperature by 1~2°C
2. Resequence control: complete humidification first, then resume cooling
3. Enter coil set temperature lower limit based on dew point temperature Evaporative humidifier water supply solenoid valve failure — irregular humidification capacity. Check: Measure solenoid coil resistance (normal: 20~60Ω) + manual flow test (apply DC 12/24V and confirm valve opens) What to do: 1. Replace solenoid valve (same bore size and voltage specification)
2. Clean water supply filter (check for debris blockage)
3. After replacement, verify continuous water supply during humidification operation

Aging Room Humidity Control Failure (Unable to Maintain 85~95%RH)

Likely causes

Humidifier nozzle clogged with lime scale — blocks within 2 weeks when water hardness exceeds 180ppm

Humidity sensor contaminated or calibration error — actual vs displayed humidity differs by 5%RH+

Excessive ventilation drawing in dry air — ventilation rate above design (over 0.5 ACH)

Cooling coil too cold causing over-humidification then condensation — coil surface below dew point

Evaporative humidifier water supply solenoid valve failure — irregular humidification capacity

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