TCO
Raypak
Thermal Cutoff Open
Display shows 'TCO' and heater shuts down; may reset after cooling.
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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
Overheating in control compartment, Blocked air circulation around heater, Failed thermal cutoff switch, Excessive ambient temperature
How to Fix / Troubleshooting
Safety first: Turn off power and gas. Allow the heater to cool.
Steps to address TCO error:
- Check installation clearances: Ensure the heater has the minimum clearances specified by Raypak on all sides for proper cooling airflow.
- Inspect louvers and grilles: Clean any dust, leaves, or debris blocking the cabinet openings.
- Verify fan operation (if equipped): Some models use a fan to cool the control compartment. Confirm it runs when the heater is operating.
- Test thermal cutoff: With power OFF, check continuity across the thermal cutoff device. Replace if open at normal temperature.
- Environmental factors: If the heater is in a small, unventilated shed or exposed to direct sun in very hot climates, consider improving ventilation or shading.
Note: Do not bypass the thermal cutoff; it protects electronics from overheating.
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Repair Difficulty
Medium
3/5
Required Part
Thermal Cutoff Switch
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