Boiler lights briefly then shuts down; display shows A02, multiple short ignition attempts before lockout.
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.
Possible Causes
How to Fix / Troubleshooting
Safety first: Turn OFF power and gas before opening the boiler. Allow the heat exchanger and burner area to cool.
Steps to troubleshoot:
- 1. Observe flame behavior (if safe): After restoring power and gas, watch through the sight glass. If the flame appears weak, lifting, or blowing off the burner, shut the unit down and proceed with cleaning and checks.
- 2. Clean burner and flame sensor: Remove the burner tray assembly per Raypak instructions. Vacuum dust and debris from burners. Use compressed air to blow out burner ports and orifices. Clean the flame sensor rod with fine abrasive pad until bright metal is visible.
- 3. Check gas supply and regulator: Ensure the appliance gas shutoff is fully open. If there is an external gas regulator, verify it is correctly oriented and not iced or damaged. A licensed technician should measure inlet and manifold gas pressure while the boiler is firing.
- 4. Inspect wiring to flame sensor and gas valve: Look for loose spade connectors, damaged insulation, or signs of overheating. Tighten and repair as needed.
- 5. Reset control: Clear the A02 lockout by cycling power or using the reset function. If flame is still lost after a few seconds of operation, the gas valve or ignition control module may be defective and should be tested and replaced by a professional.
Note: Flame instability can be caused by venting or combustion air issues. If you see signs of backdrafting or strong drafts at the burner, have the vent and air intake inspected.