installation and connection of boiler module with safety valve

Installation and correct connection of the boiler module with a bypass valve is a critical step in the installation of heating systems, where it is necessary to protect the boiler from thermal shock and ensure water circulation even when the thermostatic heads are open. This type of assembly is commonly used in non-mixed circuits, where the water temperature from the boiler does not exceed, but the circulation must be regulated. The proper function of this system depends on the precise setting of the valve and the selection of a suitable pump that can overcome the resistance in the system even at minimal heat demand.

The role of the bypass valve in a non-mixed circuit

The bypass valve (also known as a bypass) is used to bypass the heating circuit if all consumer valves (thermostatic heads) are closed. In such a case, the pressure in the system would rise sharply and the pump would work against a closed valve, leading to overheating, vibrations and damage to the pump or boiler. The valve opens automatically when the set pressure difference is reached, allowing water to circulate back to the boiler.

Technical parameters and component selection

When selecting a boiler module, it is important to ensure the compatibility of the DN diameter and pump capacity with the needs of the specific building. For most single-family homes, an unmixed module with a DN 32 diameter is sufficient, providing an adequate cross-section for water circulation even in longer pipe runs. An important component is a quality pump, such as models from manufacturers DAB or Grundfos, which have low noise levels and high reliability.

• Selecting the HEAT BLOC K31 DN 32 module without a pump allows for custom combinations according to the project.
• Ready-made solutions with an integrated DAB.EVOSTA3 or Grundfos UPM3 Auto L pump save time during installation.
• The bypass valve must be calibrated for a pressure difference of 0.5 to 1.0 bar to respond in time.

Mounting principle and valve placement

The boiler module with a bypass valve is primarily mounted on the return pipe just after the boiler, with the valve placed before the boiler inlet to ensure circulation at maximum system pressure. During installation, it is crucial to maintain pipe alignment and the correct direction of water flow, indicated by an arrow on the valve and pump body. Incorrect placement may result in the valve remaining open during normal operation, causing the water in the boiler to cool and reducing efficiency.

Connection procedure and adjustment

Before starting the system, it is necessary to check the tightness of all connections and the correct orientation of the pumps and valves. Adjusting the bypass valve requires a pressure measuring device; the valve is adjusted to open precisely when the pressure in the system exceeds the value you set (usually 0.5 bar above the operating pressure). If the valve is too sensitive, water will circulate even during normal heating, reducing the temperature difference between the supply and return lines.

1. Connect the boiler module according to the diagram, verifying the direction of water flow.
2. Fill the system with water and bleed it through the radiators and module.
3. Test the pump and bypass valve function during a simulated closure of all thermostatic heads.

Common errors and their consequences

One of the most common installation errors is incorrect setting of the bypass valve pressure, which leads to inefficient system operation. If the valve is set to a too low pressure, it will remain open constantly and the boiler will not be able to reach the desired temperature, as the water will always return. Conversely, if the valve is too stiff, it may cause damage to the pump or "water hammer" in the pipes, which is a dangerous phenomenon for older installations.

• Incorrect DN 32 diameter instead of DN 25 in large systems causes high hydraulic resistance.
• Lack of pipe insulation near the valve can cause heat loss and condensation.
• Impurities in the system can jam the valve mechanism and prevent it from opening.

Advantages of ready-made modules vs. DIY solutions

Purchasing a ready-made boiler module, such as the Boiler module HEAT BLOC K31 non-mixed DN 32 without pump, provides the assurance that all components are mutually compatible and physically arranged optimally. These modules often include pre-mounted fittings and correct distances for pump and valve installation, minimizing the risk of installation errors on site. At the same time, they offer the option to add your own pump according to the current performance needs.

An example is the boiler unit non-mixed with a discharge valve DN 32 with a DAB.EVOSTA3 40/180 pump, which is fully functional and ready for immediate use. This solution is ideal for technicians who want to have control over each component, but at the same time need a quick and safe installation without the need to assemble individual parts themselves. Another option is the apartment metering unit without a cabinet, which is used for dividing heating costs in apartment buildings.

Hydraulic separation and protection against heat loss

The bypass valve in a non-mixed circuit functions as a hydraulic separator, ensuring that the boiler pump operates at a constant flow rate regardless of the condition of the consumers in the system.

Critical pipe length and system resistance

For the proper function of the bypass valve, it is essential that the system is designed so that when all heads are fully open, sufficient hydraulic resistance is created to activate the valve only when bypassing the circuit is necessary.

Frequently asked questions

How often should the bypass valve be checked?

Annual inspection of the valve's functionality and cleanliness is recommended to prevent jamming or water leakage due to worn seals.

Can a bypass valve be used with a mixed system?

Mixed systems use three-way valves for temperature mixing, so a separate bypass valve is not necessary or suitable for this configuration.

What to do if the valve opens even with open heads?

This indicates incorrect pressure setting or valve clogging; it is necessary to reduce the valve's sensitivity or clean its internal mechanism.

Correct installation of the boiler module with a bypass valve ensures long-term and efficient operation of your heating system, protecting your investment in the boiler and pump from premature wear.

Do you have a question about this topic?

Not sure or dealing with a specific situation in your home? Write to us - we are happy to help.