What does F1 mean on a boiler?

When any error code comes up on your boiler you will probably be concerned, thinking about the cost of getting an engineer out to repair the problem, or even worse, have to buy a new boiler. However, F1 is one of the most common issues with boilers and you will likely be able to fix it yourself if you know how. That’s where this guide comes in, here we will be exploring exactly what the F1 fault means and what you can do to sort it out. 

What does the error code F1 mean? 

Essentially, if you are getting an F1 code display on your boiler it means there is a lack of pressure within your system, which is likely because there is not enough water. If you see F1, there could also be flashing lights on the front of your boiler and the system won’t work again until you increase the pressure and reset it. 

What can cause an F1 boiler fault code? 

In the most basic situation where the pressure drop is just a one-off occurrence, all you will need to do is put water in the system using a filling loop. However, if the pressure in the system keeps falling, it could indicate that you have a leak. The leak will need to be repaired before you try to increase the pressure or your boiler and maybe even your house could be vulnerable to water damage. 

How to fix an F1 fault on a boiler 

You might need to get in touch with a Gas Safe engineer, depending on the specifics of what is causing the reduced pressure. This will definitely apply to any step that involves the boiler being taken apart. 

Check the pressure sensor 

If the pressure gauge of your boiler is between 1 and 2 (1.5 bar is the optimal boiler pressure for a properly working heating system), then the pressure is not the overall issue. The role of a water pressure sensor is to inform the Printed Circuit Board (PCB) whether the pressure is too low or high. So, if the sensor is giving the PCB wrong signals, the boiler will stop working and show the F1 boiler error code. 

Determine pressure loss or not enough pressure 

If the pressure gauge is telling you that the pressure is low and it is confirmed that your sensor is not the cause, you will need to find out if the problem is coming from pressure loss or there not being enough pressure in the first place. In the case of lacking water pressure, you can top up your boiler with water using the filling loop. 

However, if your boiler is consistently dropping in pressure, it likely means there is a leak. If you don’t repair the leak before attempting to increase the pressure of the boiler, you might end up with costly repair bills as the internal boiler components can become damaged by the leaking water and potentially even your walls and floors, if the leak is originating from pipework. 

At 1.5 bar, a boiler should be stable and working normally, but if the gauge reads less than 0.5 bar the boiler will display an error message and stop working. Therefore, you will want to ask yourself if the boiler is dropping in pressure after it has been topped up. 

Identifying leaks 

Of course, the next step would be to look for any leaks in the boiler. If you have contacted an engineer, they will probably examine things like towel rails and radiators checking for pinholes, copper pipework looking for loose joints or pinholes, and the boiler’s heat exchanger and pump. A lot of the time, the source of the leak will be one of those parts, if a leak is located it needs to be fixed as quickly as possible.

Bleeding the radiators and increasing boiler pressure 

When topping up the boiler with water via the filling loop, you should keep an eye on the pressure gauge as the pressure increases. It’s important to note that as your heating system is being filled with water, air will get in as well. This leads to a blockage forming in your system that needs to be removed. 

Getting rid of the blockage will require you to bleed your radiators at the same time as topping up the boiler, so you may need some help from someone else during the process. The pressure will drop when you’re bleeding the radiators, so be sure to keeping adding water to the boiler as well as bleeding them, until all the air has been released. 

Clearing the F1 code 

Once you have found and repaired any/all leaks, increased the pressure of the boiler, and bled all the radiators, the last thing you need to do is remove the F1 code displaying on your unit and reset the boiler so it can start functioning normally again. 

Summary 

We hope you have found this guide useful, and it is the answer you were looking for to fix your boiler. If you are having other problems with your heating system and need boiler parts, NBS can help. With us, you can find the exact boiler spares you need at a much cheaper price than buying a new element, and it will come with a 12-month warranty for extra peace of mind. Explore our website today and don’t hesitate to contact us if you need help finding the part you require.