Navien Error Code E002

What Does E002 Mean?

Error code E002 indicates a communication error between the communications module and Smart Plus controller.

This fault only affects boilers with the Smart Plus remote control system.

Common Causes

1. Loose wiring connections between controller and boiler
2. Damaged communication cable along the route
3. Power supply issues to the Smart Plus controller
4. Faulty communications module in the boiler
5. Faulty Smart Plus unit itself
6. Distance too great between controller and boiler
7. Electrical interference from other devices

What You Can Do

Basic Checks

1. Check Smart Plus display - is it powered on?
2. Inspect visible wiring - look for damage or loose connections
3. Reset both units - turn off power, wait 30 seconds, restore power
4. Check for interference - move away from electrical equipment

Simple Fixes

1. Ensure tight connections at both controller and boiler
2. Replace batteries if Smart Plus is battery-powered
3. Verify power supply to the controller
4. Remove sources of interference (WiFi routers, microwaves)

When to Call an Engineer

Contact a qualified heating engineer if:

• Error persists after basic checks
• Wiring appears damaged
• Controller shows no signs of power
• Communication worked previously but stopped
• Physical damage to either unit

What the Engineer Will Do

1. Test the communication cable for continuity
2. Check signal strength between units
3. Verify power supply to both components
4. Inspect terminal connections for corrosion
5. Test communications module in the boiler
6. Test Smart Plus controller functionality
7. Replace faulty components as needed

Likely Solutions

• Re-terminate communication cable connections
• Replace damaged communication cable
• Replace faulty communications module
• Replace Smart Plus controller
• Reposition controller to avoid interference
• Install signal booster if distance is too great

Prevention

• Protect cables during any home improvement work
• Check connections during annual service
• Keep controller dry and away from moisture
• Avoid excessive cable length - use minimum required
• Route cables properly away from electrical interference

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Applicable Model: Smart Plus remote control systems.

Note: This error is specific to installations with the Smart Plus controller. If you don't have a Smart Plus system, you won't encounter this error.