How to repressurise a vaillant boiler

For more than 140 years, this brand Vaillant has been setting the standards in the heating market. They have been creating the products that have taken the markets towards a newer and better change. From water heater in early 1900’s to pioneering the combination boiler for more than 35 years, this brand has maintained its reputation around the global markets.

The Vaillant group has presence in over 20 countries with national sales companies and exports to more than 60 states. This group of heating appliances is internationally-family owned company with a heritage of more than 141 years in providing the customers efficient, energy-saving and easy to operate heating solutions for their residential and commercial use. This company stands as second largest European manufacturer in the business of heating technologies. The company develops not only in United Kingdom, but also grew in Germany, France, Spain, Italy, Slovakia, Turkey and China.

The company focuses on more to the systems with renewable energy. The development of Hybrid systems which combines with the renewable energies and heating appliances gets more focused by the brand. In all of its ranges, sustainability plays a vital role for this company. As in UK alone, replacing any old heating system with the new Vaillant one can increase the efficiency of the appliance and saves the energy up to 30%. Thus, the brand’s key element is to manufacture the products which are sustainable to the environment.

But sometimes due to any fault or an issue, your heating appliance i.e. the boiler could stop working. This can be due to the loss of water pressure in the boiler. For regaining its potential heat and warmth again, you need to repressurise you vaillant boiler. You might be thinking how will it be done? How to repressurise a vaillant boiler? We have the solution to your problem.

You just need to follow the steps, they are as follows:

  1. Close all vents

Before getting start with re pressurizing your boiler, check all the bleed valves on radiators and towel rails are fully closed.

  • Search for the filling loop

In most of the boilers, they have the external filling loop that is used to top up the boiler with water and hence increases the pressure. However, the braided hose with a small valve on it, that’s usually located below the boiler casing should be kept opened.

  • Open the filling loop

As soon as you open the filling loop, you will get to see a pressure rise. You can take a look of what is the exact pressure your boiler needs. Mostly the boilers operate with 1.5 bars.

  • Close the filling loop

Make sure that the filling loop is completely closed. However if it is not closed it will slowly leak additional water into the boiler. This will increase the pressure and the boiler will lockout.

Note –If there is no filling loop in your boiler, they might be installed on the cylinder.


 If you have re pressurized your boiler too much you will need to drain the system. But if the pressure is very high by less than 0.5 bar, you need to understand the problem by bleeding radiators. You just need to bleed key, a bucket to catch the water and towel to protect carpets. Now open the bleed valves very slowly. This will allow the water to escape and pressure to be released.

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