SunHeater
Localized Overheating / Scale Buildup
Heater frequently trips the high limit but water flow appears normal
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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
Scale inside heat exchanger, Incorrect bypass valve setting, Internal baffle damage, High inlet water temperature
How to Fix / Troubleshooting
Safety: Turn off power and gas. Allow the heater to cool before touching plumbing.
- Check bypass settings: If your system has a manual or automatic bypass around the heater, ensure it is set per SunHeater recommendations to maintain proper flow through the exchanger.
- Measure temperature rise: Compare inlet and outlet water temperatures. An excessive rise suggests restricted flow or scaling.
- Descale heat exchanger: Have a pool professional perform a chemical descaling of the Heat Exchanger using an approved descaling pump and solution.
- Verify high limit sensors: Replace any High Limit Switches that are weak or nuisance-tripping after confirming actual temperatures.
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Repair Difficulty
Hard
4/5
Required Part
Heat Exchanger
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