How to tie-in a solid fuel boiler

An efficient heating system is essential for maintaining a warm and comfortable home. A solid fuel boiler is a common choice among homeowners. These boilers produce heat through the use of fuels such as wood, coal, or pellets, offering a dependable supply of warmth during the winter. To ensure a solid fuel boiler operates safely and effectively, however, installation requires careful thought and appropriate tying-in.

Fitting in a solid fuel boiler is an essential part of any heating system installation, be it new construction or an upgrade. Tying-in is the process of joining the boiler to the current heating system and making sure everything functions as a whole. Depending on the type of boiler you have, this may entail integrating it with the electrical, plumbing, and ventilation systems in your house.

Selecting the ideal location for your solid fuel boiler is crucial before beginning the tying-in procedure. The ideal location would be one that is easily accessible for fuel delivery and maintenance, and has good ventilation. To expedite the tying-in process and save costs, take into account the area’s proximity to the plumbing and heating infrastructure that already exists.

It is crucial to ensure adequate ventilation when installing a solid fuel boiler. The combustion gases produced by these boilers must be safely evacuated from your house in order to reduce the possibility of carbon monoxide accumulation. Making sure your home has enough ventilation shields your family from dangerous emissions while also encouraging efficient combustion. When designing the ventilation system for your boiler, make sure you adhere to the manufacturer’s instructions and any applicable local building codes.

After deciding on a location and taking care of any ventilation needs, it’s time to connect your solid fuel boiler. In order to complete this process, the boiler must be connected to the heating distribution system in your house, which may consist of radiators, underfloor heating, or both. To finish the tying-in procedure safely and successfully, you might require the knowledge of a certified professional, depending on how complicated your heating system is.

Step Description
1 Choose the location for the solid fuel boiler.
2 Ensure proper ventilation in the boiler area.
3 Install a concrete base for the boiler to sit on.
4 Connect the boiler to the chimney for exhaust.
5 Install a backflow preventer to avoid water contamination.
6 Connect the boiler to the heating system.
7 Install necessary safety features, like a pressure relief valve.
8 Test the boiler to ensure proper functioning.

One important factor that sticks out in the world of home insulation and heating is connecting a solid fuel boiler. To get the most out of your heating system and maximize its effectiveness, this procedure is crucial. A solid fuel boiler can be easily added to your home’s current heating system to provide dependable warmth while cutting down on energy waste and utility expenses. The secret to getting the best performance and comfort in your house is knowing how to connect a solid fuel boiler correctly, whether you’re replacing your heating system or adding renewable energy sources.

What is the difference between solid fuel boilers

Apart from their ability to burn diverse kinds of solid fuel, heat generators differ from other heat sources in several ways. When connecting a solid fuel boiler to a water heating system, these features ought to be considered as standard. What makes them up to:

  1. High inertia. At the moment there are no ways to sharply extinguish the ignited solid fuel in the combustion chamber.
  2. Condensate formation in the fuel compartment during heating up. The peculiarity is manifested due to the entry of a coolant with a low temperature (below 50 ° C) into the boiler tank.

Note: Only one type of solid fuel unit—pellet boilers—is devoid of the inertia phenomenon. They have a burner in them where wood pellets are dosed; almost instantly, the flame goes out when the feeding is stopped.

The heater’s water jacket could overheat due to inertia, which would cause the coolant inside to boil. The production of steam results in high pressure, which ruptures a portion of the supply pipe and the unit’s casing. As a result, the furnace room is overflowing with water, there is a mountain of steam, and the solid fuel boiler is no longer fit for use.

Erroneous construction of the heat generator’s piping can lead to this circumstance. Ultimately, during the standard operating mode of wood boilers, the unit achieves its peak efficiency at this point. Smoldering and combustion continue in the furnace until the thermostat closes the air damper in response to the temperature reaching 85 °C. Before it stops growing, the water’s temperature must rise by an additional 2-4 °C, or even more.

A safety group is always a crucial component in the piping of a solid fuel boiler in order to prevent overpressure and the ensuing accident; this topic will be covered in more detail below.

The formation of condensate on the fuel box’s interior walls as a result of the still-unheated coolant seeping through the water jacket is another unpleasant aspect of the unit’s operation on wood. This condensate is not at all God’s dew; rather, it is an aggressive liquid that rapidly corrodes the combustion chamber’s steel walls. The condensate then becomes a sticky substance when combined with ash, making it difficult to remove from the surface. Installing a mixing unit in the solid fuel boiler piping circuit solves the issue.

It’s best not to let owners of heat generators with cast-iron heat exchangers—who don’t mind corrosion—to celebrate too soon. They might be in for more trouble yet—cast iron can be destroyed by temperature shock. Imagine that the water supply to the solid fuel boiler in a private home was cut off for twenty to thirty minutes, along with the circulation pump. Because of the same inertia, the water in the heat exchanger has time to heat up during this period and the water in the radiators has time to cool down.

The pump activates, directing the cooled coolant from the closed heating system to the heated boiler as soon as electricity appears. A sudden change in temperature causes the cast iron section to crack, the heat exchanger to experience a temperature shock, and water to leak onto the floor. It is extremely difficult to fix, and replacing the section isn’t always an option. Therefore, even in this situation, the sub-mixing unit will stop an accident—more on that later.

The descriptions of emergency scenarios and their aftermath are not meant to frighten users of solid fuel boilers or persuade them to purchase extraneous piping scheme components. Practical experience, which is the foundation of the description, should always be considered. The likelihood of such events is incredibly low when the thermal unit is connected correctly; this is nearly the same as when heat generators powered by other fuel types are used.

How to connect a solid fuel boiler

Two key components are present in the conventional solid fuel boiler connection scheme, which enables the boiler to operate dependably in a residential heating system. As seen in the figure, this safety group and mixing unit is built around a three-way valve that has a thermal head and temperature sensor.

Note: The expansion tank should be connected to the heating system’s return line prior to the pump (in the direction of water flow); it is not shown here in the typical configuration.

The provided scheme, which can be used with any solid fuel boiler, including pellet boilers, demonstrates how to connect the unit correctly. There are many popular heating schemes that include a heat accumulator, indirect boiler, or hydrostrelka; these schemes do not always include this node, but they do require it. In the video, the following technique for preventing moisture precipitation in the furnace is covered in detail:

The safety group’s job is to automatically reset the network pressure when it exceeds the predetermined value, which is typically 3 bar. It is installed directly at the solid fuel boiler’s supply pipe outlet. This is the function of the safety valve, but the element also has a pressure gauge and an automated air vent. While the second one regulates pressure, the first one lets go of the air that has formed in the heating medium.

Take note! Any type of shut-off valve cannot be installed on the pipe segment connecting the boiler and safety group. Take the handle off the stem if you have provided a ball valve to cut off and repair parts of the group.

How the scheme works

This algorithm governs how the mixing unit, which shields the heat generator from condensate and temperature changes, operates, beginning with stoking:

  1. The wood is just burning, the pump is switched on, the valve on the heating side is closed. The heat carrier circulates in a small circle through the bypass.
  2. When the temperature in the return pipeline rises to 50-55 ° C, where there is a surface-mounted sensor of remote type, the thermal head on his command begins to press on the stem of the three-way valve.
  3. The valve slowly opens and cold water slowly enters the boiler, mixing with hot water from the bypass.
  4. As all the radiators warm up, the overall temperature rises and then the valve closes the bypass completely, allowing all the coolant to flow through the unit"s heat exchanger.

Vital. The 3-way valve is used in conjunction with a unique head that has a sensor and capillary that are intended to control the water’s temperature within a specific range (such as 40–70 or 50–80 degrees). This is not the place for an ordinary radiator thermo-head.

This piping layout is the most straightforward and dependable; you can safely install it with your own hands, ensuring the solid fuel boiler operates safely. There are a few suggestions in relation to this, particularly when connecting the wood heater in a private residence using polypropylene or other polymer pipes:

  1. The section of the pipe from the boiler to the safety group should be made of metal, and then lay plastic.
  2. Thick-walled polypropylene is a poor conductor of heat, because of which the overhead sensor will be blatantly lying, and the three-way valve – delayed. For the correct operation of the unit, the section between the pump and the heat generator, where there is a copper bulb, should also be metal.

The location of the circulation pump installation is another consideration. The ideal location to stand is on the return, ahead of the wood boiler, as indicated by the diagram. Generally speaking, you can turn on the pump when the supply is turned on, but keep in mind the previous point: in the event of an emergency, steam could emerge in the supply pipe.

Since the pump cannot pump gases, the impeller and coolant circulation will stop when the chamber is filled with steam. Because the water flowing from the backflow will not be cooling the boiler, this could hasten its potential explosion.

A way to reduce the cost of piping

Installing a three-way mixing valve with a simplified design, which eliminates the need to connect a thermal head and an overhead temperature sensor, can reduce the cost of the condensate protection system. The pump already has a thermostatic element installed, and it is configured to operate at a constant mixture temperature of 55 or 60 °C, as seen in the figure:

Note: Several well-known brands, including Herz Armaturen, Danfoss, Regulus, and others, manufacture these type of valves, which are intended for installation in the solid fuel boiler’s primary circuit and maintain a constant temperature of mixed water at the outlet.

Installing such a component undoubtedly enables TT-boiler pipework cost savings. However, the coolant’s ability to be adjusted using the thermal head is also lost, and the deviation at the outlet can be as much as 1-2 °C. Generally speaking, these drawbacks are negligible.

Variant of piping with buffer tank

Here are some reasons why using a buffer tank is highly recommended when operating a boiler on solid fuels. The unit must run in maximum mode in order to function properly and generate heat with the efficiency specified in the passport (varying from 75 to 85% depending on the type). The efficiency of burning wood decreases when the air damper is closed to slow down combustion because there is less oxygen in the furnace. Carbon monoxide (CO) emissions into the atmosphere rise concurrently.

As a point of reference. It is illegal to run solid fuel boilers without a buffer tank in the majority of European countries due to emissions regulations.

However, in contemporary heat generators, the coolant temperature reaches 85 °C at maximum combustion, and a single stack of wood only lasts for four hours. For many private home owners, this is not ideal. Installing a buffer tank and integrating it into the boiler’s plumbing to function as an accumulator tank is the fix for the issue. Schematically, it appears as follows:

The buffer tank loads (technically, stores heat when the firebox is burning full) and transfers that heat to the heating system when it dies. On the opposite side of the accumulator tank, a second pump and a three-way mixing valve are also positioned to regulate the temperature of the coolant supplied to the radiators. Now that the furnace has been turned off, the house’s heating will provide a buffer tank for a while, negating the need to run to the boiler every four hours. The heating temperature and volume will determine how long it takes.

Aid. The following formula can be used to calculate the heat accumulator’s capacity based on actual use: A tank that has a minimum volume of 1 m³ is required for a private residence that measures 200 m².

There are a few significant subtleties. You need a solid fuel boiler with enough capacity to load the buffer tank and heat it simultaneously for the piping scheme to function safely. This indicates that two times as much power will be needed as the design capacity. A further consideration is choosing a pump capacity such that the boiler circuit’s flow rate marginally surpasses the heating circuit’s water flow rate.

In the video, our expert demonstrates an intriguing variation on connecting the TT-boiler with a homemade buffer tank (also known as an indirect boiler) without a pump:

Joint connection of two boilers

Many homeowners install two or more heating sources that use different energy carriers to improve comfort when heating their homes. Currently, the most pertinent boiler combinations on:

  • natural gas and wood;
  • solid fuel and electricity.

In light of this, gas and solid fuel boilers ought to be connected so that, upon burning the subsequent firewood, the second boiler takes over for the first one. The plumbing requirements for an electric boiler and a wood boiler are the same. When a buffer tank is used in the circuit, it can be easily implemented because, as the figure below illustrates, it also functions as a hydraulic shooter.

A separate publication contains information on how to calculate the volume of a buffer tank as a tip.

As you can see, two separate boilers can serve multiple heating circuits simultaneously, including warm floors and radiators, in addition to loading the indirect heating boiler, because of the presence of an intermediate tank-accumulator. However, not everyone installs a heat accumulator with a TT-boiler because it is an expensive pleasure. Here’s a straightforward plan that you can install with your own hands:

Note: The program is applicable to solid-fuel boilers that operate in tandem with electric and gas heat generators.

Here, a wood heater serves as the primary heat source. The room thermostat’s sensor detects the drop in air temperature that occurs after the firewood is burned, and the electric boiler kicks on to heat the house right away. The solid fuel unit’s pump is turned off by the mechanical thermostat when the supply pipe’s temperature drops in the absence of a fresh load of wood. Everything will occur in reverse order if it is ignited after some time. The following joint connection method is explained in detail in the video:

Strapping by the method of primary and secondary rings

To serve a large number of users, a solid fuel boiler and an electric boiler can be connected in another way. This technique, which uses primary and secondary circulation rings, allows flows to be hydraulically separated without the need for a hydrostrelka. Despite the scheme’s apparent complexity, the system requires very little electronics for reliable operation, and no controller is required at all:

The trick is that supply and return pipes are connected to a single main circulation ring that houses all consumers and boilers. The head of the pump in the main circuit experiences a minimal pressure drop because of the short distance (up to 300 mm) between the connections. This indicates that the flow of water in the main ring is independent of the secondary rings’ pump systems. The heating medium’s temperature is the only variable.

The main circuit can theoretically contain an infinite number of secondary rings and heat sources. Making the right choices regarding pumping unit capacity and pipe diameters is crucial. The flow rate in the most "voracious" secondary circuit must be less than the actual capacity of the main ring pump.

In order to accomplish this, a hydraulic calculation must be completed; only then will it be feasible to choose the pumps appropriately, meaning that the typical homeowner cannot accomplish this without professional assistance. Additionally, disconnecting thermostats must be installed in order to connect the operation of electric and solid fuel boilers, as shown in the video below:

Comfort and financial savings depend on your home having effective insulation and heating. Installing a solid fuel boiler is one important component of this. The proper way to connect a solid fuel boiler to your current heating system has been outlined in this article.

Selecting the appropriate kind and size of solid fuel boiler for your house is crucial, first and foremost. You should evaluate your heating requirements. Take into account elements like your property’s size, its insulation, and the kind of fuel that is readily available where you live.

Setting up the installation site comes next after you have chosen the right boiler. This include giving the boiler a room of its own, making sure it has enough ventilation, and modifying your current heating system as needed.

For your solid fuel boiler to operate efficiently, proper installation is essential. To guarantee that the installation is completed correctly and safely, it is essential to adhere to the manufacturer’s instructions and, if required, seek professional assistance.

Regular maintenance is necessary to keep your solid fuel boiler operating efficiently after installation. This include giving the boiler a thorough cleaning, checking for wear or damage, and making sure the fuel supply and airflow are adequate.

In conclusion, installing a solid fuel boiler into your house’s heating system is a big financial commitment that will pay off in the long run in terms of cost savings, comfort, and energy efficiency. You can have dependable and effective heating for many years to come if you follow the instructions in this article and continue to be vigilant about maintenance.

Video on the topic

Correct piping of an industrial solid fuel boiler | Boiler room by mind

✅Binding of solid fuel boiler with your own hands. ✅Video instruction.

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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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