Display shows E04 and the Sime water heater will not start; fan may not run.
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.
Possible Causes
How to Fix / Troubleshooting
Safety: Disconnect power before removing the cover. Do not bypass safety devices like the air pressure switch.
Steps:
- Visual fan check: With the cover removed, gently spin the fan impeller by hand (power off). It should rotate freely without scraping. If seized or noisy, the fan assembly may be failing.
- Inspect pressure switch tubes: Remove the silicone tubes from the air pressure switch and fan housing. Blow through them to ensure they are clear. Reconnect firmly, ensuring no kinks.
- Check flue terminal: Confirm the external flue is not blocked, as this can prevent the pressure switch from closing.
- Test operation: Restore power and call for hot water. Listen for the fan starting. If the fan runs but E04 remains, the pressure switch may not be closing and likely needs replacement.
Professional help: Replacement of the fan or air pressure switch and verification of correct operation should be done by a qualified Sime service technician.
Repair Difficulty
Required Part
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