Weil-McLain
Overheating Domestic Hot Water
Water is too hot at faucets; temperature fluctuates and may exceed safe levels.
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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
Stuck tank aquastat contacts, Faulty temperature sensor, Maladjusted mixing valve, Boiler control DHW setpoint too high
How to Fix / Troubleshooting
Safety first: Risk of scalding is high. Warn occupants and avoid using hot water until the issue is corrected.
- Lower setpoints: Reduce the DHW temperature setting on the boiler control or tank thermostat to 120°F temporarily.
- Check mixing valve operation: If installed, adjust the thermostatic mixing valve to a lower setting and verify that cold water supply to the valve is not shut off.
- Test aquastat or sensor: If the tank continues to heat beyond the setpoint, the aquastat or tank sensor may be stuck closed or reading incorrectly and should be replaced.
- Verify control logic: Ensure the boiler is not locked in DHW priority mode indefinitely due to a sensor fault, causing continuous heating.
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Repair Difficulty
Medium
3/5
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