Vornado EvapoCare 15 Temperature Sensor Malfunction How To Diagnose

When the Vornado EvapoCare 15 displays a flashing red light or fails to reach the set temperature, a common culprit is a faulty temperature sensor. Even a small fault in this component can throw the entire humidification cycle off balance. This guide walks you through the diagnostic process step by step, giving you the confidence to determine whether the sensor is the source of the problem and how to proceed from there.

Understanding the Role of the Temperature Sensor

The EvapoCare 15 relies on its internal temperature sensor to keep the humidifier at the correct humidity level. The sensor feeds real‑time data to the control board, which then adjusts the fan speed and the vaporizer’s water flow. When the sensor misreads the temperature—either too high or too low—the unit either stops working, produces too much mist, or runs at a constant high speed.

Because the sensor is located inside the humidifier’s casing, it is protected from routine cleaning but is still exposed to the high moisture environment that can cause corrosion or electrical shorts over time.

Common Symptoms of a Malfunctioning Sensor

• Red LED Blinks Quickly
  A rapid blinking of the power light usually indicates a sensor error.

• Unit Does Not Warm Up
  If the humidifier stays cool and does not produce mist after several minutes, the sensor may be reporting an incorrect temperature.

• Fan Runs at Constant High Speed
  The EvapoCare 15 has three fan speeds. If the fan locks into the highest setting and never slows, the sensor may be stuck at a high‑temperature reading.

• Error Codes on Display
  Some models show an error code that corresponds to the sensor, often “T” or “TEMP.”

• Unexpected Shut‑Down
  The unit may cycle off after a short run, which can happen when the sensor detects a temperature spike it cannot correct.

Safety Precautions Before You Begin

1. Turn Off and Unplug – Disconnect the unit from any power source.
2. Remove Water Reservoir – Empty the reservoir to avoid spills during disassembly.
3. Work on a Clean Surface – Use a flat worktable and keep a small towel nearby.

Step‑by‑Step Diagnosis

1. Verify the Power and Firmware

Before blaming the sensor, check that the unit’s firmware is up to date and that the power supply is functioning correctly.

• Firmware Check – Some EvapoCare models allow firmware updates via a companion app or USB connection. If an update is pending, install it and see if the issue persists.
• Power Supply Test – Plug another appliance into the same outlet. If the outlet is faulty, replace it or use a different one.

If both power and firmware are fine, move on.

2. Inspect the Water Reservoir and Filters

The sensor can be affected by the amount of water and the condition of the filters.

• Clean the Reservoir – Residue and mineral build‑up can interfere with sensor readings.
• Replace Filters – A clogged filter can cause temperature spikes in the humidifier’s chamber.

After cleaning and replacing, reset the unit and observe whether the blinking stops.

3. Listen for Anomalies in the Fan

Place your ear close to the fan housing.

• Unusual Noises – A rattling or high‑pitched whine often signals fan damage rather than a sensor fault.
• Fan Speed Lock‑In – If the fan does not slow when the unit reaches the target humidity, the sensor might be misreporting a higher temperature.

Note any irregularities for reference when you inspect the electronics.

4. Test the Sensor with a Multimeter

The EvapoCare 15’s temperature sensor is a thermistor that changes resistance with temperature. You will need a digital multimeter capable of measuring resistance (Ω) to test it.

What You Need

• A pair of insulated wires
• A digital multimeter
• A heat source (e.g., a hair dryer)
• A cooling source (e.g., a small ice pack)

Procedure

1. Locate the Sensor – Remove the front panel of the EvapoCare 15. The sensor sits on the base of the humidifier, near the fan housing.
2. Disconnect the Sensor – Carefully detach the wiring harness.
3. Measure Resistance at Room Temperature – Record the reading. A typical reading should be within the manufacturer’s spec sheet (usually around 10 kΩ at 25 °C).
4. Apply Heat – Warm the sensor gently with a hair dryer. The resistance should drop. Record the new value.
5. Apply Cooling – Cool the sensor with an ice pack. The resistance should rise. Record the value.

If the sensor’s resistance does not change with temperature, it is defective. Even if the resistance changes, compare the readings to the spec sheet; a sensor that is too sensitive or not sensitive enough can still cause errors.

5. Examine the Wiring Harness

Wiring damage can create a short that mimics a sensor failure.

• Look for Cracks or Frayed Strands – Inspect all visible wires for wear.
• Check for Loose Connections – Ensure every pin is seated firmly.
• Test Continuity – With the unit off, use the multimeter in continuity mode to verify that each wire runs without interruption.

If you find a broken or damaged wire, repair or replace it before proceeding.

6. Reassemble and Test

After you have verified or replaced the sensor and any damaged wiring, put the unit back together.

1. Reconnect the Reservoir – Fill it with clean water.
2. Power On – Observe the LED light pattern.
3. Set a Target Humidity – Monitor whether the unit reaches and maintains it.

If the LED no longer blinks rapidly and the unit operates normally, the sensor was indeed the problem.

What to Do If the Sensor Is Faulty

A. Replace the Sensor

The EvapoCare 15 sensor can be purchased from the manufacturer or authorized retailers.

• Ordering – Search for the part number that matches the model year.
• Installation – Follow the same steps used to remove the old sensor.

B. Seek Professional Repair

If you are uncomfortable working with electronics or if the unit continues to misbehave after replacement, contact Vornado customer support or a certified appliance repair technician.

C. Consider Replacement of the Unit

For older models where parts are scarce, it might be more economical to replace the entire unit. Compare the cost of parts and labor with the price of a new EvapoCare 15.

Preventive Tips to Extend Sensor Life

• Regular Cleaning – Use a vinegar solution to dissolve mineral deposits in the reservoir and on the sensor.
• Avoid Overheating – Never leave the unit unattended for extended periods in a hot environment.
• Use Filtered Water – Distilled or deionized water reduces mineral buildup.
• Check Firmware Updates – Manufacturers sometimes patch sensor calibration issues.

Common Misconceptions

Troubleshooting Flowchart

While a diagram cannot be embedded directly, imagine the following logical path:

• Power & Firmware OK?

  • Yes → Proceed to Reservoir & Filter
  • No → Update firmware or replace power supply

• Reservoir Clean?

  • Yes → Fan Anomalies?
  • No → Clean reservoir

• Fan Speed Normal?

  • Yes → Sensor Test
  • No → Inspect fan components

• Sensor Test Passes?

  • Yes → Unit Works → Problem solved
  • No → Replace sensor or contact support

Summary

Diagnosing a Vornado EvapoCare 15 temperature sensor malfunction involves systematic checks of power, firmware, reservoir cleanliness, fan behavior, and the sensor itself. By following the steps outlined above, you can determine whether the sensor is truly at fault and take appropriate action—whether that means a simple replacement or a call for professional service.

Remember to always prioritize safety by unplugging the unit and working on a clean surface. A clear understanding of the sensor’s role, coupled with careful testing, will help you restore the EvapoCare 15 to reliable operation and maintain a comfortable, healthy environment in your home.