Vaillant were the first manufacturer to develop a combi boiler and have been at the forefront of combi boiler technology ever since. They have a great reputation for manufacturing and reliability. Vaillant is the only brand to have been awarded the Quiet Mark accreditation by the International Eco-Award Scheme to manufacturers of the quietest products. Vaillant has dedicated engineers for warranty repairs and have dedicated training centres across the uk for engineers to keep their knowledge up to date with their boiler advancements.

Fault 1: Code F22

When F22 shows on the boiler display this indicates the water pressure is low. You can check the pressure gauge dial on the front of your boiler if it has one, or newer models the digital display will show how much pressure is in the system. Once topped up to the desired pressure the error F22 error code will disappear. In some instances you may have to press reset on the boiler. Ideally the pressure will need to be between 1.0 and 1.5 bar. This is an easy fix that anybody can attempt however if you put too much pressure in the system don’t panic. Just bleed a radiator till the pressure drops to the required level.

Newer Vaillant Boilers have a built in filling loop under the boiler. These levers are grey and there will be two of them, one either side directly underneath the boiler. They will have closed written on them. Each valve (lever) should be in the quarter to 3 position (imagine it being a clock) open the right valve first to the 12.30 position then open the left valve till you have the desired pressure.  

Watch this video from vaillant to see how easy it is. 

Fault 2:  F75

If you get F75 showing on the boiler display, this is probably going to be the pressure sensor that is blocked and cannot detect the pump spinning and the increase in pressure when the boiler goes to fire up. It may also be a faulty pump. This commonly happens on boilers and systems that have not been properly flushed to remove sludge or have not had a magnetic filter fitted. The easiest solution is to get a Gas Safe Engineer to replace the sensor.

Fault 3: Codes F27 & F28

These two codes commonly refer to a frozen condensate pipe. Generally this is the white drain pipe underneath your boiler that goes outside to a drain and it has frozen in the cold weather. This causes a build up of water that backs up to the boiler causing it to stop working/ lock out to error and f27/f28 will appear. This is generally an issue because the waste pipework is not a large enough diameter or the pipe is run horizontally or slightly uphill causing the waste pipe to freeze in very cold weather.

An easy fix is to run hot water from a kettle over the pipe to defrost the ice. This may take a long time and in extended bouts of freezing weather it will repeatedly freeze up. You could disconnect the pipe under the boiler if you feel confident enough and put a container there to catch the water. Beware when doing this initially there will be a lot of water. 

The ideal situation is to either upgrade the pipe to a larger diameter or consider running the pipe to an internal waste if possible or consider a trace heating kit that activates in freezing weather to stop the pipe freezing up.

Only attempt these fixes if you feel confident to do so, if you’re in doubt, always use a Gas safe Engineer.

Fault 4: Code F28 (Vaillant Turbomax)

This fault is very common for the Vaillant Turbomax, caused by a faulty ignition, or no gas getting to the boiler. The faulty ignition leads to no spark being generated. Alternatively there may be a gas valve issue or if you are on a meter check you have credit as you may have run out of gas.

In this instance you will need to get a Gas safe Engineer out to fix the issue.

Fault 5: Code F62

Before being able to fix the fault, a heating engineer will first need to find the cause, because there are several possible reasons why you’re seeing the F62 error, such as:

The gas valve is jammed stuck
There is an issue with the PCB (printed circuit Board) communicating with the gas valve.

In some instances both gas valve and PCB can be at fault. You will need the services of an Engineer to determine what the underlying cause of this fault is.


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