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E06

medium severity

Defrost Cycle Error

The automatic defrost cycle is not completing properly, which can lead to ice formation in the heat exchanger during cold weather. This reduces efficiency and can cause system shutdown.

Common Causes
What typically triggers this error code
  • Defrost sensor failure
  • Defrost damper stuck or malfunctioning
  • Control board defrost logic error
  • Excessive outdoor humidity combined with cold temperatures
  • Heat exchanger partially blocked
Symptoms to Watch For
Signs that indicate this error
  • E06 error code on display
  • Visible ice formation in heat exchanger
  • Reduced airflow in cold weather
  • System cycling on/off frequently in winter
  • Water dripping from unit
Troubleshooting Steps
Step-by-step DIY troubleshooting guide
1

Turn system off to allow complete thaw (2-4 hours)

2

Check defrost drain for blockages

3

Inspect heat exchanger for ice buildup after thaw

4

Verify outdoor temperature sensor is working

5

Restart system and monitor for recurring error

Important: If these steps do not resolve the issue or you are uncomfortable performing them, contact a professional HVAC technician immediately.

Preventive Maintenance
How to avoid this error in the future
  • Clean heat exchanger core annually before winter
  • Test defrost cycle at start of heating season
  • Ensure proper drainage from unit
  • Monitor system performance during extreme cold
Frequently Asked Questions

Why does my HRV freeze up in winter?

Freezing occurs when moisture in exhaust air condenses and freezes in the heat exchanger. A properly functioning defrost cycle prevents this. If freezing persists, contact us for inspection.

Should I run my HRV during extreme cold?

Yes, HRV systems are designed for year-round operation. However, during extreme cold (below -25°C), some systems may cycle more frequently or require lower fan speeds.

Related Error Codes
Other codes you might encounter

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