For boiler builders it is very important to use the right seals in the construction of their central heating boilers. Seals are widely used in the construction of these boilers. These ensure safety and a long service life of the boiler. Which seals are most suitable differs per part of the boiler. In this article we explain which seals are best used for which parts in the construction of your central heating boiler.
A good design is half the battle
NDS-Seals is specialized in the production and design of various rubber, silicone and plastic seals. In order to prevent failing sealing constructions in your boiler, it is very important to start with a good design of these seals and constructions. It is important in the design of your boiler to ensure that sealing constructions are easy to assemble and replace. In addition, of course, practice must be taken into account. Think for example of higher temperatures or larger tolerances. For advice about the sealing construction in your boiler, please feel free to contact us:
Material requirements specific to each part of the boiler
In the past twenty years there have been many developments in the field of rubber seals. Endurance tests have shown how different types of rubber age. The rubber is exposed to condensate, a high temperature or a combination of these for a long period of time. It is then determined how strongly the rubber material is influenced by this load. The compression set, for example, is an important value that is measured before and after the tests. With this knowledge, the choice of rubber material can be tailored to its application.
Different types of rubber material are therefore suitable for different applications. A central heating boiler consists of various parts, each with its own function. Each component therefore requires its own type of sealing. In the first generation of HR boilers, things often went wrong in this area. The constructions were too complicated and the wrong materials were used. Below you can find out which materials are most suitable in seals for the next parts of your central heating boilers:
The burner is a part of the boiler in which certain components are exposed to high temperatures. Exposure to (heavy) chemical loads can also occur. In order to guarantee a long life of a burner and associated seals, it is important that the correct FKM and/or silicone materials are used. In addition, in the engineering phase it is important to prevent the burner seal from being exposed to too high temperatures as much as possible.
The sealing of the burner in your boiler is a very critical seal. If it does not suffice, this can cause damage to the boiler or even lead to the escape of flue gases. NDS-Seals has special simulation and test equipment to test critical seals in series.
The heat exchanger in a central heating boiler is often subject to condensate loading and relatively low temperatures. This makes EPDM an extremely suitable material for seals in the heat exchanger of your boiler. The high quality materials that NDS-Seals offers for this application are provided with an EN14241-1 certification.
Through the end of the heat exchanger, the flue gases are discharged to the flue gas outlet. In many boilers, a connecting piece or adapter is used to connect the air supply and flue pipe to the boiler.
The seals used are mostly EPDM materials. However, in some situations an FKM or silicone seal is used. All materials that are used in the flue gas outlet of your boiler must be inspected and meet the requirements as laid down in standard EN14241-1.
At the bottom of the heat exchanger there is a condensation drain. This drain ensures that the condensation is drained away. The condensate drain is usually connected to the sewerage system. The correct operation of the condensate drain (usually a siphon) is crucial. In the event of a malfunction, the boiler can (partially) blow the flue gases into the sewer system. This is an undesirable and dangerous situation.
Qualitative seals in this part of the boiler are very important, because the siphon is often located partly outside the boiler. Leakage could mean that the condensate and the flue gases could enter the house or room where the boiler is installed.
The gas regulating block ensures that the burner receives the correct amount of gas (air) mixture. A number of safety devices are built into this control unit. These ensure that the gas supply is cut off under certain conditions.
Seals in this part of the boiler are often EN549 certified. Materials that are often used are NBR, FKM and silicones.
A hr combi boiler takes care of both the central heating and the hot water supply. In this part of the boiler, seals are used that comply with quality marks for the drinking water industry. These are often WRAS, KIWA, KTW, ACS, DVGW W270 and NSF61. However, each country has its own certification requirements. The quality marks include requirements for the ingredients used to manufacture rubber seals.
Seals from NDS-Seals
Many boiler malfunctions are related to the seals. NDS-Seals can protect you from this. The use of the right materials and the creation of smart constructions is crucial for the seals in central heating boilers. NDS-Seals helps you to develop a good design. We can ensure that the production of your boilers is simplified and (cost) more efficient.