How to Fix / Troubleshooting

Safety first: Turn off power before accessing internal components.

Monitor display: Watch for any brief error messages or temperature spikes just before shutdown; this can indicate which safety is opening.
Improve water flow: Clean filters, open valves, and increase pump speed to ensure stable flow through the Thermeau heater.
Check venting: Inspect exhaust for partial blockages that could cause flue temperatures to rise.
Inspect control compartment: Ensure the control board area is not excessively hot and that ventilation openings are clear.
Test safety switches: A technician can test high limits, flow switch, and flue sensor for intermittent operation and replace any weak components.

Heater starts normally but shuts off after a few minutes, long before reaching set temperature.

Possible Causes