A06
Hoval
Flue Gas / Air Pressure Switch Fault
Boiler locks out with A06, display may indicate flue or air pressure error
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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
Blocked flue or condensate trap, Faulty air pressure switch, Incorrectly connected pressure hoses, Condensate in pressure tubing
How to Fix / Troubleshooting
Safety: Turn off power. Flue and condensate work must maintain boiler sealing and comply with regulations.
- Check condensate trap: Locate the Hoval condensate trap under the heat exchanger. Ensure it is not blocked with sludge. Remove and clean with water, then refill with clean water before refitting.
- Inspect pressure hoses: Verify that the silicone hoses to the air pressure switch are correctly connected (high/low pressure ports) and not kinked or split. Replace if hardened or damaged.
- Flue inspection: Check for visible obstructions at the flue terminal. If internal flue blockage is suspected, contact a technician to dismantle and clean.
- If A06 persists, the air pressure switch or differential pressure sensor should be tested and replaced by a professional.
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Repair Difficulty
Hard
4/5
Required Part
Air Pressure Switch / Differential Pressure Sensor
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