Vaillant Boiler F61 Fault – Error Code Guide

The Vaillant F61 error code affects the EcoTec models of Vaillant boiler. It signifies a problem with the gas valve, although other causes such as a faulty PCB are possible.

This error must be diagnosed and addressed by a Gas Safe Engineer, and parts may need replacing.

What Does a Vaillant F61 Error Mean?

The F61 error code means that there is a fault with the gas valve, which can be dangerous and needs addressing immediately. The boiler will have locked out for safety, and you shouldn’t try to restart it.

The gas valve is what controls the flow of gas into the boiler, and it works in conjunction with the thermostat and PCB to make sure the boiler is running correctly and that the temperature and water pressure are correct.

When there is a gas valve error, the PCB will recognise the incorrect gas flow, shut the boiler down and display the F61 error code.

What Causes a Vaillant F61 Error?

Seized or Stuck Valves

Mechanical components do degrade over time, and gas valves are no exception. 

In most F61 cases, the gas valve has seized or got stuck; a valve stuck open can allow gas to enter the combustion chamber, and a valve which is stuck closed will starve the boiler of gas. 

Both these situations can be dangerous, and the appearance of an F61 error will trigger a lockout.

Connection or Wiring Problems

Loose wiring and damaged connections are problems that can occur with age due to the vibrating parts within the boiler, such as the pump or van. This problem can also be a result of water damage caused by a leak within the boiler.

A Fault in the Gas Valve

Over time a gas valve may become so worn and/or damaged that it no longer works and can’t be repaired. Valves like this will not work effectively and this will trigger an F61 fault code.

PCB Fault

The PCB (printed circuit board) is the central hub of the boiler which keeps tabs on all its parts, and controls when error codes are displayed. 

If there’s a problem with the wiring between the gas valve and the PCB (or a fault within the PCB itself), then the boiler will lockout and it could cause the F61 code to show even though the gas valve is perfectly operational. 

However, this is only occasionally the cause of an F61 code and it should be treated as a gas valve error.

Faulty Thermocouple

One of the things an engineer will check is whether the pilot light is on; if it is, then this narrows the problem down to the thermocouple, which is what provides the energy to open and close the gas valve.

If this isn’t working, then the gas valve can’t open and close properly. Causing incorrect gas flow and triggering the F61 error.

How to Fix a Vaillant F61 Error

Since the F61 error relates to gas and the gas valve, it must be dealt with by a Gas Safe Engineer.

A seized or stuck gas valve will need to be freed and tested to see if it is safe to use or reparable. If the valve is damaged or faulty, it may need replacing to get your boiler safely working again. 

Similarly, if the thermocouple is causing the problem, then this part will need replacing.

If the problem is a connection or wiring issue, then an Engineer will identify and fix these issues, but will commonly replace the gas valve as well to ensure that the boiler is safe to use.

If the fault lies with the PCB, the most common cause for this is an internal leak with the boiler.

While these leaks in themselves can be fixed, and a damaged or faulty PCB is replaceable, it is very expensive and time-consuming. You will be better off investing the money in a new boiler.

Can you Fix a Vaillant F61 Error Yourself?

The F61 is not an error you should attempt to fix yourself. 

Since it is gas related, you must call a Gas Safe Engineer as diagnosing and attempting to repair a gas valve issue without the appropriate certification is unsafe, and is likely to result in a costly misdiagnosis.

However, although an F61 rarely signifies a problem with your gas supply or a gas leak it is wise to turn off your gas supply until an engineer arrives to look at the boiler.

Does an F61 Error Mean my Boiler is Broken?

Most often, an F61 error is caused by a faulty part; either the gas valve or the thermocouple. 

These parts can be repaired or replaced, and any connection or wiring issues can usually be fixed. 

However, if the fault lies with the PCB then it is best to get a new boiler; PCBs are replaceable but it is very costly to do so, and you will be better off investing in a new boiler altogether.

Is it Safe to Use the Boiler With An F61 Error Code Showing?

No. This is a gas-related error and any gas related error can be dangerous. 

The boiler will lockout when this error code shows anyway, so you will not be able to accidentally use the boiler while the error code is showing. 

It is unlikely that an F61 will signify a gas leak, but it is safest to turn off your gas supply while an engineer is being called.

Do I Need to Reset my Vaillant Boiler After An F61?

Usually, a boiler needs resetting after an error has been repaired, which an engineer will do for you, but you should not try to clear the F61 error code by resetting the boiler. 

It may allow the boiler to work again for a short while, but very quickly the PCB will detect the same error again and cause the boiler to lockout. 

The only way to get rid of the error code is to call an engineer and have the problem fixed.

How Much Does a Gas Valve Replacement Cost?

A gas valve replacement can cost up to £300, and unfortunately, an engineer is unlikely to have the correct part to hand and will have to order it; so you may have to wait a few days for the repair to be carried out.

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