Vaillant boilers and corrosion

Hi Guys

I just purchased and installed new boiler as my old one was really corroded and could not seal properly. I was thinking this time I would take care better about my boiler. Any suggestions how to effectively protect my boiler from corrosion?


Hi Craig,

For the preservation of the boiler and its lifetime, to have it last for longer years, you need to clean it carefully and delicately. One of the main reasons that cause corrosion is using chemical solutions that decay the metal exterior and can possibly ruin the system or the controls if the corrosion spreads. Please do not use cleaning sprays, solvents, chlorinated cleaners, or any other chemical components near or on the boiler. You also shouldn’t try this with the infrastructure or the flue system; the harmful chemicals in cleaning agents can rust the boiler. In order to clean the boiler, please only use a damp towel or cloth with a small amount of chemical-free soap to wipe the exterior, without getting the interior wet.

Vaillant- frost protection

Hi Guys,

I plan to spend winter in another country and I was wondering if I need to protect my Vaillant boiler from frost for the time me being  away- like I need to take care of fridge or other electronic equipment. Any thoughts, experiences?


Hi Keith,

Frost damage can affect the boiler and even ruin parts of the heating system; this is common during winter, and especially in cold places. The first thing you need to do is make sure that the room’s heating system is activated at a moderate temperature and isn’t too low. Please do not try to add preservations like frost & corrosion protection or other agents without consulting a heating specialist company. This can possibly damage the system, digraphs, and cause unpleasant noises while heating.

Be sure to take all the necessary precautions when you’re traveling or away such as confirming the power and heat are activated at all times so the room temperature is stabilized and for extra measure, ask the heating specialist to drain the heating system and the boiler (while it is switched off). However, when your boiler was installed, it was connected to the power mains and so an alternative solution would be to make sure it stays connected and that it is switched on at the on/ off switch. Your boiler is equipped with a frost protection mode, so when the temperature drops, if the switch is on, the system automatically heats the heating system, preventing frost damage. If you’re leaving in warmer seasons, you can just close the gas isolator cock and the cold water valve.


Vaillant- I think I can smell the gas around my combi boiler

Hi Folks

I have Vaillant combi boiler, which is 5 years old, so far no problem with it, but recently I feel a gas smell around the boiler. Is that normal?


Hi Alex,

Smelling gas from the boiler is most likely due to poor installation and errors while installing. A gas leak is very dangerous and needs to be handled immediately because it can lead to poisoning or an explosion. First, you need to provide enough ventilation by opening all the windows and doors then turn off the boiler and be sure to contact your heating specialist as soon as possible. However, if you hear gas leaking, all individuals must leave the house or office then immediately call 0800-111-999, the national phone number for gas emergencies.As a safety precaution to avoid danger in the future, please be sure to never store any flammable items like paper, oil, alcohol, or paint near the boiler.

Vaillant fault code F22

Dear All

Why did the boiler switch off and display fault code F.22? I don’t understand… Help please


Hi Josh,

Fault code F.22 means your boiler’s heating system has a low filling pressure and needs to be fixed because it can damage or burn the boiler. The bar graph display on the right side of the screen shows the pressure level, the normal pressure level should be between the dotted sections in the middle, the 0.1 to 0.2 MPa, where the heating system is cool.

However, if the level drops down to 0.8 MPa then it’s too low and the bar graph starts flashing. Within a minute, the maintenance sign, an open-ended spanner appears. It eventually drops to the lowest level, 0.5 MPa so the boiler shuts down and the display screen shows the F.22 code. In order to fix this issue, you must re-fill the heating system. When the system has a sufficient amount of water, the error code disappears after approx. 20 seconds.

The screen displays current filling pressure with the lowest and highest pressure level. Be sure to always check the pressure level and make sure it is moderated (topped with water). If the pressure keeps dropping, contact a heating specialist for further assistance.


Vaillant combi boiler leaking pipes

Hi Folks

I am having a bit of a problem with leaking pipes around my combi boiler. What should I do?


Hi Dave,

A leak in the pipes can cause the whole boiler to stop operating. This means one of the pipes was punctured or poorly installed and it will also release a hissing sound when the boiler is on and being used. The pipework may need to be replaced but for a temporary fix, you will need to close the cold water stop valve that connects between the draw-offs and the boiler.

The Vaillant boiler does not come with a cold water stop valve but it was probably provided and installed when installing the boiler. The boiler won’t operate as long as the water is stopped. Contact a heating specialist company to check the pipes and maintain the problem.

Vaillant boiler- why am I getting a maintenance signal but no fault code

Hi Folks

I have Vaillant combi boiler and very strangely I get a maintenance signal but no fault code. Has anyone met with the same.


Hi Dan

When you get a maintenance signal (the open-ended spanner) without a fault code that means something in the boiler (maybe more than one thing) needs fixing. In this case, you need to select the Live Monitor section from the menu to check the overall status of the boiler. Open the main menu by pressing the two selection buttons together or you can get it through the screen.  

The live monitor includes the status code for each condition and a clear text message of what it means to avoid any confusion. It also updates automatically with any changes in the boiler so you can regularly check the boiler status to reassure nothing goes wrong.

Pro 28- how do I fill up the heating system?


I have Vaillant Pro 28 and I would like to fill up the heating system. Any directions?



Hi Joe,

It is very important to always keep the heating system topped with water to avoid damaging the boiler. You can fill up the heating system yourself in a few simple steps, use the filling cock (a device that fits into the heater) to put tap water into the heating system. You can reassure you got the right balance by checking the filling pressure display on the screen. The best level of pressure is between 0.1 and 0.2 bars.


Vaillant Plus 831- how do I set the hot water temperature?

Hi Folks

I have Vaillant Plus 831 and I am not sure how to properly set the temperature. Any help?


Hi Adam

To set the heat of the water to your preferred temperature, you click on the left-side button and the temperature display shows on the screen. Then you press the minus or plus button to increase or decrease the temperature. When you settle on a temperature, confirm it by clicking on the right-side button. Simple, right?

If you don’t want to wait for the water to heat up and are in a hurry, you can quickly set it to comfort mode. Comfort mode is instantly setting the heat of water to your desired temperature. To activate this option, press the left-side button then the right-side button afterward, the “C” sign will appear displaying comfort mode. You can also turn off the heating mode altogether during the warm seasons by activating the summer mode. Press the right-side button and the heating flow temperature will appear then keep pressing the minus button until you reach “Cylinder charging off” and confirm with the last press of the right-side button.

Beware of scalding with high water temperature (above 60 °C) especially in the case of children or elderly people

Exclusive 838- no hot water

Hi All

As of today I have no hot water. I have Vaillant Exclusive 838, any ideas what is wrong?



Hi Ben

There can be many reasons that lead to the boiler not providing hot water; however, there is also a set of solutions to try. First off, please make sure that the boiler is switched ON at the on/ off switch. Then you need to check if the flame is ignited, if not then it needs amending. You can try to check the gas isolator cock because it could be clogged; and if that didn’t work then confirm that the heating flow temperature and hot water are set to the right degrees.

If after all these attempts it still didn’t work, you need to check the heating system. The filling pressure can be too low and needs to be topped with water or there may be air in the system and the radiators need to be cleaned. Before taking action with any of these steps, please refer back to the “Live Monitor” section for a status on the boiler. If you can’t get hot water running yourself, you may need to reach out to a heating company to have a look at your boiler.  

EcoMAX 613- can I install the boiler myself

As much as we’d love to believe it is that simple, unfortunately, it isn’t. Installing a boiler requires precise setting up and accuracy. Please do not try to install it yourself and refer back to a professional heating agency. They have the required equipment, will follow the known regulations, and are well aware of the standard gas and heat temperatures. And most importantly, they will perform the needed tests to make sure everything is working well. Setting up the boiler yourself can be time consuming, dangerous, and an inefficient setup. Your specialist will inform you with any extra parts (valves, agents… etc.) that are needed for installment and get things done quickly.