What it means
Vaillant words F.61 differently in different places. Its installation manuals call it a fault in the gas valve assembly control. Its online code list says the control chips (the ASIC or microcontroller) don't run in the defined times. Both point to the gas valve's control and the circuit board.
What to check, in order
- Don't keep resetting it
Vaillant says this is a case for an expert, and trying to solve it yourself can be dangerous.
- Call a Gas Safe registered engineer
Or Vaillant on 0344 736 0049. Have the boiler's model and the code ready.
When to call a Gas Safe engineer
Vaillant lists a fault in the gas valve's electrical connection, a short circuit in its wiring, a faulty gas valve or a faulty circuit board (PCB).
A repair visit will usually check the wiring first, then the boiler's control board.
- Note the model and serial number. They're on a label on the data badge, usually under the boiler or behind the front cover.
- Write down the exact code, and what the appliance was doing when it appeared.
- Check whether it's still under warranty. If it is, the repair may cost you nothing.
Quick answers
What does the Vaillant F61 fault code mean?
The boiler's control electronics can't operate the gas valve the way they should, so it has shut down. Vaillant words F.61 differently in different places. Its installation manuals call it a fault in the gas valve assembly control. Its online code list says the control chips (the ASIC or microcontroller) don't run in the defined times. Both point to the gas valve's control and the circuit board.
Can I fix Vaillant F61 myself?
Engineer only (engineer visit). Start with: don't keep resetting it; call a Gas Safe registered engineer. Vaillant lists a fault in the gas valve's electrical connection, a short circuit in its wiring, a faulty gas valve or a faulty circuit board (PCB).
Is Vaillant F61 worth repairing?
Deal with it now. It concerns how the gas valve is controlled, so it's a safety matter. Have it checked rather than resetting it.
Checked against
- Vaillant: boiler fault codes list
- Vaillant ecoTEC plus open vent installation and servicing instructions (PDF)
- Vaillant ecoFIT pure combi installation and maintenance instructions (PDF)
Last reviewed October 2026. Manufacturers update their pages, and your manual is the final word. Spotted a mistake? Email contact@appliance-error-codes.com.