How to Fix the F28 Error on Vaillant Boilers

The F28 error on your Vaillant boiler is an indication that there is a problem with the fuel supply. In addition to insufficient fuel, this problem could also be caused by a worn-out gas valve or heating flow NTC thermistor. If you are unsure of what the problem is, check the manual or contact a Vaillant dealer.

Insufficient fuel supply causes error F28 in Vaillant boilers

When you see the error code “F28” on your Vaillant boiler, it means that the appliance’s burner has failed to light. This can be caused by a few things, including a faulty ignition lead or electrode, or it can be caused by a gas supply problem. To fix this error, you will need to contact your gas company.

First, check your gas valves. If they are faulty, or are outdoors, you may have a leak. In this case, insulating the gas valve is necessary. Secondly, check your gas meter. This is a potentially hazardous DIY job. Alternatively, you can contact a Gas Safe engineer.

A stuck valve is another common cause of the F28 error in Vaillant boilers. It is usually not too difficult to repair, as long as it is unstuck. However, if the valve is too worn, you should replace it. A valve replacement will cost about PS300. You can also check your spark electrodes, which are a vital part of your boiler’s ignition. In some cases, they will have cracked or lost their continuity.

Worn-out spark electrodes

If your Vaillant boiler has been having problems, it may be due to worn-out spark electrodes. These parts need to be replaced if they’re at fault. Unfortunately, you can’t do this on your own, and you’ll need to contact a professional engineer to replace the spark electrodes.

Worn-out spark electrodes can cause your Vaillant boiler to lock out or show fault code F28. A gas safe registered engineer can diagnose this issue quickly and safely, and the spark electrodes can be easily replaced. You can also try resetting the thermostat. This will return the boiler to optimum pressure.

The first step is to inspect the ignition system. This component is the hub of the boiler and connects all the electronic components. A faulty PCB or wrongly connected wires can cause problems. In other cases, the ignition system may be defective. If this happens, the spark electrodes may be too worn-out or the wire connecting them to the PCB is faulty.

Heating flow NTC thermistor interruption

When you are trying to figure out what is causing your heating flow NTC thermistor to interrupt on a Vaillant boiler, it is vital that you first check the pump and repressurisation settings. If the pump is running at low capacity and not getting enough water, the problem could be due to a variety of factors, including air trapped in the system, or a pump malfunction. Other causes may include a short circuit in the cable loom connecting the gas valve to the control panel or a defective electrode lead.

A common cause of this error code is a short-circuited flow NTC. You must ground the heating flow duct if the error persists after you fix the short-circuit. In addition, the sensor is located behind the gas valve connecting to the fan, and the failure may be either electrical or mechanical. The sensor may be damaged or faulty, or the filter cap may be wet or blocked. Another common cause is that the gas flow pressure is too low.

A Vaillant boiler has an effective system of error codes that can identify faults and provide solutions for these faults. We’ve broken down the most common problems you might encounter and include helpful illustrations and tables.

Worn-out gas valve

A worn-out gas valve on a Vaillant boiler can be a major problem. It can cause the boiler to become inoperable or even to lock up. To get the boiler working again, you should contact your heating engineer. They should be able to diagnose the problem and offer a replacement if necessary.

When your boiler shows the F61 fault code, it is most likely the gas valve is out of order. While it may not sound like a major issue, it is dangerous if the valve is stuck. A repair company will be able to remove the valve from the boiler and free it.

The number one cause of this error is a blockage. Insufficient gas supply or a faulty electrode or ignition lead can cause the gas valve to malfunction. In some cases, the valve can be stuck open, allowing gas to pass through but not the boiler. Whether the error is related to a gas valve or a blockage, it is always important to get it repaired by a Gas Safe registered engineer.