E07
State
Combustion Fan / Blower Failure
State tankless water heater displays E07 and will not fire; fan may not start.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Failed combustion blower motor, Seized blower wheel, Loose or damaged blower wiring, Faulty control board fan relay
How to Fix / Troubleshooting
Safety: Disconnect power and gas. Vent components may have sharp edges; wear gloves.
- Access blower: Remove the front cover. Locate the combustion blower assembly connected to the venting.
- Spin test: Try rotating the blower wheel by hand. It should spin freely without grinding. If seized, the blower must be replaced.
- Check wiring: Inspect the blower motor connector and harness for burns or loose pins. Reseat connectors.
- Voltage check: With a qualified person and proper precautions, restore power and command a call for hot water. Measure voltage at the blower connector. If correct voltage is present but the blower does not run, replace the blower. If no voltage, suspect the control board.
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Repair Difficulty
Hard
4/5
Required Part
Combustion Blower Assembly
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