Connection of indirect heating boiler to the boiler. 3 proven schemes

An indirect heating boiler can greatly improve comfort and efficiency when it comes to home heating system optimization. With this kind of arrangement, you can have plenty of hot water without the need for a direct heat source by using your main boiler to heat water, which is then circulated through a separate storage tank. To get the most out of an indirect heating boiler and guarantee dependable operation, you must know how to connect it correctly.

You can integrate an indirect heating boiler with your current boiler system using one of several popular integration schemes. Every configuration emphasizes flexibility in installation and use while accommodating various household needs and pre-existing setups. Understanding these schemes can assist you in selecting the best solution for the particular needs of your home, whether you’re installing a new system or updating an outdated one.

You will be guided through three tested indirect heating boiler connection schemes by this article. Our goal is to provide you the information necessary to make wise choices regarding your home heating system by breaking down each procedure step-by-step. We’ll also discuss the benefits of each strategy, enabling you to see why and how these configurations might work well for your house. Connecting an indirect heating boiler can be simple and greatly increase the efficiency of your home’s heating system if you have the right information.

Scheme Description
Basic Configuration This simple scheme connects the boiler and the indirect heating boiler directly. It uses the boiler"s heat to warm up the water in the indirect heating boiler, suitable for small homes.
With Three-Way Valve This setup integrates a three-way valve that directs the flow between the heating system and the indirect boiler, optimizing the use of heated water and ensuring efficient heating during higher demand.
Advanced Circuit with Circulation Pump Includes a circulation pump that ensures constant water movement between the boiler and the indirect heating boiler. This scheme is ideal for larger homes, providing consistent hot water supply and improved heating efficiency.

Without the need for an additional heating source, you can greatly improve your hot water supply by connecting an indirect heating boiler to your current home boiler system. Three dependable schemes for integrating an indirect heating boiler are presented in this article, along with information on the required parts, the setup procedure, and how each configuration meets various household requirements. These tried-and-true schemes provide workable solutions that can be customized to meet your unique needs, guaranteeing a steady supply of hot water with increased heating efficiency, whether you’re trying to maximize energy efficiency, make accommodations for a small space, or need a robust system that can serve a large family.

Principle of operation

Boilers wall-mounted, floor-mounted, and integrated with an integrated thermal heating element and heat exchanger. In indirect heating boilers, a built-in coil typically takes the shape of a stainless steel pipe, in contrast to TEN water heaters, where there is direct contact with the heater. The basic idea of operation is to transfer heat to the water in the tank by having the coolant travel along the coil.

This system of operation reduces the amount of limescale that forms, heats water considerably faster than it would with a traditional heating element, and increases the likelihood that the tank won’t require maintenance.

We’ll examine the indirect heating boiler wiring diagrams in this article:

  • to the wall-mounted gas boiler;
  • Connection to a floor standing gas boiler;
  • electric boiler;
  • to a solid fuel boiler.

Connection diagrams

Connection to a wall-mounted single-circuit boiler

Wall-mounted gas boilers typically have a valve that controls the transition between the boiler heating circuit and the heating element, as well as an integrated circulation pump. In this instance, installing a three-way valve or circulation pump is not necessary. It suffices to purchase a temperature sensor for the boiler, connect the supply and return pipes, and operate the entire system.

An illustration of how to connect a Buderus Logamax U072 boiler to an indirect boiler. Every connection is nearer the wall that is behind the boiler.

The heat transfer fluid is supplied to the top of the heat exchanger from the boiler, travels through a coil, and then returns via a pipe to the boiler. To make sure that when water enters the tank, the indirect heating boiler is connected to the boiler according to this principle. The comparatively colder part of the heat exchanger heats it up first, followed by the hotter part.

Diagram showing how to connect a wall-mounted single-circuit boilerto an indirect heating boiler

There has to be a shut-off valve between the two systems on the supply and return. Ball valves are mounted directly on the water heater or on the inlet and outlet, close to the boiler. A quick disconnect connection is used to connect to the boiler. This connection makes it simple to maintain or, in the event that it becomes necessary, replace the boiler.

If a ball valve is installed near the boiler on the supply and return, then split connections are installed between the valve and the water heater. Wall-mounted single-circuit boilers are connected to the indirect heating boiler by different schemes – if there is only one output, let"s say supply, then the return can be common with the heating system. There are 2 outlets, both supply and return. Some electric boilers and gas boilers do not have an outlet for piping the indirect boiler. In this case it is necessary to purchase a boiler connection kit. But, the kit should include a valve and servo motor, which should be used to connect to the boiler automatics.

With a Baxi Ecofour gas boiler as an example, this is how it appears:

Additionally, a Baxi Luna 3 boiler set will already be in this condition (the boiler itself already has a three-way valve):

Connection to a floor standing single circuit boiler

In theory, connecting to a first-type single-circuit boiler is identical to connecting to a second-type boiler. Additionally, they have a supply and return system, in which the bottom returns the return and the top feeds the supply. The only subtlety is that an air lock can form in the upper portion. An automatic air vent must be installed in order to stop this.

How can a floor-standing boiler be connected to an indirect boiler? You will need to install a circulation pump or a 3-way valve in addition to the boiler because floor-standing boilers lack an integrated pump and 3-way valve. Let’s examine the plan in more detail to see how to connect the floor boiler to the boiler using a circulation pump.

The floor-standing gas boiler is directly connected to the boiler’s return using tees. Put in a circulation pump either on the supply or return side. Remember to install a ball valve before and after the pump, a filter, and a check valve in addition to the shut-off valves. We install split connections when connecting the boiler; the ball valve is only installed on the return because we have already installed a ball valve on the supply near the pump. When using this connection scheme, the boiler automation controls the pump, which turns it on and off based on when the boiler needs to be heated.

Connecting via a manifold or hydrostrel

The supply and return from the boiler, each with a separate pump, are connected after the hydrostrip in the second connection type. Following the installation of the hydrostrelka, collector wiring is typically connected with separate pumps. This can be seen, for instance, on the floor heating contour, on the radiator circuit, and also connected to the boiler’s heating circuit. This will require additional automation, which will manage all of the pumps in this scheme as well as the boiler.

This connection plan works well for large two- or three-story homes. The supply leaves the boiler and travels to the collector, where it is distributed to the indirect boiler and the heating systems on each floor.

The only remaining issue is figuring out when to heat the tank. In order to accomplish this, mount a thermostat and connect it to the circulation pump using an immersion bulb. The thermostat tells the pump to turn on when the boiler cools down, and vice versa.

Although there are other ways to connect the boiler and boiler, we only discussed the most widely used ones here.

Connection to a two-circuit boiler

In addition to heating, two-circuit boilers serve as flow water heaters and supply hot water to users. Closing the hot water supply tap from the DHW circuit is required in order to use the boiler solely for heating or hot water, that is, to connect the boiler to a two-circuit boiler and simultaneously make it single-function.

After purchasing a specific boiler pipe kit, you connect the boiler as a single-circuit boiler.

Connecting the accumulator

Consider the connection of the boiler on the scheme of hot water supply – how the wall-mounted gas boiler, connected to the boiler, warms the heat exchanger. Cold water, rising through the pipe, passes through the coarse filter and then goes along the wall, straight to the boiler. Before connecting the cold water pipe to the boiler, it is necessary to install a ball valve with a split connection, which should be directed towards the tank. Then a safety check valve, a so-called two-in-one valve, must be installed. After that, install a tee to connect the hydroaccumulator (expansion tank), and only then connect the cold water pipe to the boiler.

The procedure listed above must be precisely followed when connecting cold water:

  • ball valve;
  • safety check valve;
  • expansion tank;
  • connection to the boiler.

Installing this type of pipework close to the boiler, or at the inlet, is ideal. The water heater typically comes with the boiler’s safety check valve. Should it be missing from the set or misplaced, it must be purchased. A safety check valve can be purchased already assembled or separately, meaning that you can purchase the safety valve and check valve separately and connect them to one another. Following the ball valve, cold water should go to the expanded tank via the safety valve, check valve, and safety valve.

An example of a boiler safety valve

Before you buy a safety check valve, you should check the boiler data sheet to see at what pressure it should operate. Thus, we have supplied cold water to the boiler, as we have tied everything correctly. At the outlet of hot water we only need to install a ball valve with a split connection, which should be installed between the valve and the boiler. If necessary, an expansion tank for the boiler can also be installed on the hot water outlet, for this purpose a tee is installed between the tap and the boiler and the expansion tank is connected. The tanks are universal, for hot or cold water supply or only for hot water supply. The main thing that the water temperature was working – up to +70 degrees.

Hot water supply should not be provided by expansion tanks—these are meant for heating purposes only. For DHW systems, expansion tanks are chosen based on the boiler’s capacity. Generally speaking, at least 10% of the entire volume.

Selecting hydroaccumulators with a small amount of reserve is advised:

  • for 150 liters – 18 liter tank;
  • 200 liters – 25 liter tank.

An effective and practical way to enhance your hot water supply is by connecting an indirect heating boiler to your home boiler system. Homeowners who integrate these systems can benefit from a steady and dependable supply of hot water, especially in larger households or during periods of high demand. The three well-established plans we covered offer alternatives for different house plans and plumbing setups, so there’s a good option for practically any circumstance.

Important energy savings can also result from the implementation of these connection schemes. Because they make use of the heat produced by the main boiler that would otherwise be wasted, indirect heating boilers are renowned for their efficiency. Together, these two benefits maximize energy efficiency and lower total heating expenses. As a result, selecting the appropriate installation plan is essential to optimizing these advantages, and it’s recommended to speak with an expert to ascertain the best configuration for your particular requirements.

Ultimately, installing an indirect heating boiler may seem like a difficult task due to its technical aspects, but the long-term benefits make the investment worthwhile. Homeowners should strongly consider this upgrade due to its potential cost savings, improved hot water supply reliability, and increased energy efficiency. The installation process can be expedited and the efficiency and cost-effectiveness of your home’s heating system guaranteed with the help of skilled technicians.

Video on the topic

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Sergey Ivanov

I like to help people create comfort and comfort in their homes. I share my experience and knowledge in articles so that you can make the right choice of a heating and insulation system for your home.

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