Sime water heater displays E07 and stops; may occur after long operation.

Safety: Turn off power and close water and gas valves. Allow the unit to cool completely before touching internal parts.

Steps:

• Reset overheat thermostat: Locate the manual reset overheat thermostat on the heat exchanger (small button in the center). Press gently until you feel a click. If it immediately trips again, do not keep resetting.
• Check water flow: Ensure inlet filters on the cold water connection are not blocked. Clean any mesh filters.
• Descale heat exchanger (basic): If your area has hard water, scale can cause localized overheating. A full chemical descaling should be done by a technician, but you can flush the system with clean water and ensure any external filters/softeners are maintained.
• Inspect for restricted piping: Check that isolation valves on inlet and outlet are fully open.

Professional help: Repeated E07 indicates serious overheating. A Sime technician should inspect the primary heat exchanger, overheat thermostat, and internal hydraulics.