- At the location of the water tank
- Sauna stove with boiler
- What you need to know about operation
- Coil for furnaces
Having made the right choice of heating equipment, you can steam and wash without purchasing and installing a boiler. A reliable, modern, spacious heat exchanger for a bath will perfectly cope with the role of a heater: it will be able to supply the required volume of hot water to the storage tank. In this article you will learn about the options and operating features of the technical tool that exist today, practical advantages and the most popular models.
What it is
The device is used to heat water in the bath. Its operating principle is based on the physical properties of hot water, expanding and rising upward, while cold water remains below.
Typically the heat exchanger is small in size, so the liquid in it heats up quickly. Two pipes are connected to it - below and above. Thus, hot water through the upper pipe, replaced by cold water from below, rises into the tank, which can be located either in the steam room or in an adjacent room, usually in the sink. In this case, low-temperature water is constantly added to the heating device through the lower pipe without forced supply.
Options for heating water in a bath from a stove
The following models are distinguished:
1. Samovar-type container - installed on the outlet pipe of the chimney. Heating occurs due to the heat of the flue gases escaping into the chimney. A tap for dispensing hot water is connected to the fitting at the bottom of the tank. If you don’t have a washing machine, then this option will be an excellent solution for heating. We recommend paying attention to the following operating conditions:
- the use of a samovar-type tank is allowed only with bathhouse stoves;
- It is prohibited to operate an empty tank while the stove is operating;
- If you want to get a “Finnish sauna”, this option for heating water will not suit you, since if the steam room is heated for a long time, the liquid will begin to boil, which is why heavy steam is formed.
2. A samovar-type heat exchanger (small in size with the ability to connect to a tank), which can be located anywhere. It is convenient because, if available, the tank can be placed in the washing room. One of the obvious advantages over other options is that it quickly heats the water.
3. Heat exchanger, which is installed on the starting chimney.
4. Starting chimney + tank-backpack - an option with being in a steam room and the absence of controlled convection to warm up the room. The container comes into contact with the wall of the chimney pipe, due to which the liquid is heated. Among the disadvantages, it can also be noted that this model does not have protection from hard infrared radiation, and in case of strong heating, the water begins to boil.
5. Convector chimney with a heater built into it.
Features: the register is located inside a pipe from which 2 identical ¾-inch fittings with internal thread come out. Using pipes, the device is connected to a tank hanging in a convenient place.
May be:
- Built into the oven - when scale appears, it loses efficiency.
- Located near the chimney (on it) - it provides heating to the required temperature more slowly, but nothing settles on its inner surface, it is easy to access, and its repair is not difficult.
The choice depends on the user: what to give preference to, performance or ease of maintenance, saving usable space or fuel.
Selection of materials
The choice of material for the heating tank only seems simple. The most common option is steel. The main advantage is low cost and ease of manufacture using conventional welding operations. However, in the conditions of a Russian bath at constant high temperature, high humidity and exposure to superheated steam, this material quickly rusts and its service life is short. In addition, water in a rusty container may take on a corresponding tint. Protection using paint coatings will not work due to the risk of fire when coming into contact with a heated oven. The painted structure can be used in a system with a heat exchanger.
Another option is cast iron. In a cast iron container, the water takes a long time to heat up, but it also takes a long time to cool, which makes it possible to retain heat even after the furnace has stopped firing. Disadvantages: heavy weight, high price and problems with corrosion.
The best option is stainless steel. Of course, it is much more expensive than ordinary steel sheet, but it does not corrode and can last for many years. The most common steel grades for the manufacture of sauna heating tanks are 8-12X18H10 (304) and 08X17 (430). Stainless steel containers are quite light, have excellent thermal conductivity, and the coefficient of deformation during sudden temperature fluctuations is negligible.
In principle, it is possible to use ready-made enameled tanks. However, such containers are good as long as the enamel protective coating is intact. When the slightest chips appear, active corrosion begins
This means that enameled tanks require increased caution during operation, which is very difficult to ensure.
The question of how to heat water in a bathhouse is decided independently, based on specific conditions. The simplest option is to install a standard tank heated by heating elements and manually deliver it to the destination point in small containers.
Difference by type
The simplest designs of heat exchangers are coils with ends removed from the tank: one takes in liquid at room temperature, the other releases hot liquid.
More complex ones are a system consisting of two metal tanks with anti-corrosion properties - cylindrical and rectangular in shape with connecting pipes.
At the location of the water tank
There are two ways:
- This photo shows an option for installing a heat exchanger in a steam room and a tank in a wash room.
- The second option is to install a heat exchanger with a tank inside the steam room.
Advantages of installing a heat exchanger in a steam room
- high water heating speed;
- saving free space in the steam room;
- Wide range of options for installing the tank - in a steam room or in a shower room.
Tin pipe
Tin as a material for smelting a heat exchanger is very practical and reliable. Essentially, a chimney with a heat exchanger for a bath will look like a pipe wrapped around a smaller metal or copper tube. During the heating process from the tube, the air passing by will also warm up.
It will be enough to weld the spiral tube. Soldering can also be done with tin, previously degreased with orthophosphate acid. In this case, the heat exchanger will be secured especially securely, because it is not without reason that tin samovars are considered the standard of reliability among analog products.
Features of installation and operation of the heat exchanger
Installed between the firebox and convector:
- built into the oven;
- attached to the chimney;
- or built into it.
The productivity of the device with a capacity of 5 liters is enough to quickly fill a 120-liter tank with hot water. It’s easy to use – just organize a timely supply of liquid (uninterrupted operation can be ensured by using a circulation pump) and “feed” the firebox with firewood.
When installing a heat exchanger (recuperator) for a bath, the following points must be taken into account:
- the total length of pipes for water supply should be laid at 3 m, which minimizes heat loss;
- with a connecting pipe diameter of 1 inch, it is permissible not to use a circulation pump.
The longer the heat exchanger is in use, the more justified the installation is from an economic point of view.
Rules for installing a heat exchanger on a sauna stove
The following rules must be followed:
- The heat exchanger must consume no more than 10% of the total energy produced by the furnace, then the latter will operate with good efficiency.
- The pipes must be laid so that the water flows by gravity, that is, at a 250-degree slope on the direct supply and 30-degree on the return one.
- It is important to reserve power for cooling after fuel burns.
- It is necessary to provide a sufficient volume of water for each individual model, because if there is too little of it, it will boil quickly, which can lead to the formation of deposits on the walls and a fire hazard, and if there is too much, you will have to wait a long time before taking a shower.
How to connect a heat exchanger if the tank is in a steam room:
- The entrance to the hot water tank should be at least 5 cm higher than the upper register fitting. This is necessary for better circulation.
- The upper register is from 1.4-1.5 m from the floor, despite the fact that the podium under the stove is 15 cm. The bottom of the tank in the steam room should be at least 1.5 m, and preferably higher.
- If the tank is 0.5 m high, then we have a total installation of 2.0 m. That means there is still half a meter to the ceiling. And here the question arises: how to fill the liquid. If there is a running water supply, then water will flow without problems.
Second connection option: we place the tank lower, and place the fitting for the supply circuit on the side. But there is a nuance: if the water level is below the upper fitting, there will be no circulation. It will stand in the heat exchanger and periodically reach a boil, but in the tank it will remain cool.
If you need to place the tank in the wash room, you should follow the same principles as when placing it in the steam room.
How and how to connect the external tank to the heat exchanger
Remember that the elements in contact with the stove become hot, their surface temperature exceeds 100 0C. Therefore, the pipes must be made of stainless steel (cast iron will not work, as it is susceptible to corrosion). But ordinary pipes are allowed to be made of metal-plastic; they can even be replaced with flexible hoses. The main thing is that the diameter is 1 inch or 3/4, otherwise the circulation will be poor.
Use tangit for seals, and paronite for fittings. Feel free to replace factory elements with non-standard ones, but made of heat-resistant material. Don't forget about the drain valve - it is simply necessary to preserve the system for the cold season or to quickly remove stagnant liquid. Otherwise, during frosts, the remaining water will freeze and burst the pipes.
Briefly about the main thing
If a classic wood-burning stove is used to heat the bath, then a heat exchanger must be installed in the storage tank to heat the water. It will significantly reduce costs. For example, there will be no need for an electric boiler.
The operating principle of the heat exchanger is very simple. But there are many designs. The owner will have to choose the most acceptable one only individually. Because there is no universal way. And you just need to decide on the spot which one is best suited. And the decision will be influenced by the material from which the stove is made and the location of the storage tank.
Ratings 0
Review of furnaces with heat exchanger
There are built-in models of heat exchangers. Below we will look at the popular ones.
Sauna stove with boiler
Let's start with how justified such a decision is from an economic point of view. Installation of this device increases the efficiency of the equipment used. With it, exhaust gases not only fly away uselessly into the atmosphere, but also simultaneously heats water, which can then be used for bathing or other household needs. Therefore, it repeatedly justifies the fact of its installation in the long term.
Vesuvius Skif 16 VChT
Powerful and fast, with a right- or left-side location of the water heater, equipped with a mesh. It boasts a steel firebox with thick walls (8 mm), thanks to which it is not afraid of even constant exposure to high temperatures.
Tornado 20M2
Productive, heavy (125 kg). Equipped with a cast iron door, built-in heat exchanger and a spacious side casing designed for 240 kg of stones. Must be installed on a reinforced foundation. But the efficiency is impressive.
Harvia 20SL Boiler
A heater from a Finnish manufacturer, weighing 75 kg, with 40 kg of stones. Modern, with a recuperator in the form of a tank, with a remote structure and a built-in condenser, designed for a steam room with an area of up to 20 m3. It has stable legs and a stainless frame, has smooth shapes and an attractive design.
Installation and connection of the heat exchanger and tank in the bath
- Find a suitable location to mount the remote tank. If all the structural parts are located in one room, it is most often hung on the wall closest to the heating unit, 200-300 mm above the recuperator.
- Secure the wooden dies with dowels - these are the guides on which you will hang the tank. This is necessary so that the container does not touch the interior elements with its hot surface.
- Strengthen the assembly with brackets for greater reliability.
- Equip the remote tank with 4 pipes, then, using fittings, connect the first two with the corresponding ones at the tank (for direct and reverse water supply), close the third with a valve, and connect the shower (faucet) to the fourth.
- Install (at the lowest point) a valve on the reverse line to drain the water.
- Connect all elements and check the system for leaks.
What you need to know about operation
If you have read the instructions and purchased a heat exchanger for your bath, make sure that the following conditions are met:
- Fastening connections must be movable - this will help minimize deformation of the recuperator components under the influence of high temperatures.
- Seals must be made of heat-resistant materials.
- The capacity of the remote tank is selected so that it can accommodate the volume of water heated in 2 hours.
- It is important that full compatibility with the heating unit is maintained.
- The device should consume no more than 10% of the energy generated by the oven.
Operational safety
To prevent emergency situations, observe the following precautions:
- do not attach pipes directly to walls;
- Make sure that there is always enough water in the tank, otherwise you will quickly encounter a scale problem or even a fire hazard;
- constantly check the operation of the device and sound the alarm if it suddenly breaks down;
- Use only heat-resistant gaskets and regularly pay attention to their condition.
The simplest heat exchangers
To make choosing a unit easier, we suggest you familiarize yourself with the following options.
Coil for furnaces
The simplest version of a heat exchanger is a pipe (made of aluminum, copper or other ductile and anti-corrosion metal), bent into a spiral or, less commonly, of a different shape. The carrier effectively moves along it by gravity if its total length is less than 3 m. It is heated by hot air, and not by contact with fire. At the ends of this design, threads are made (external) for a fitting connection with the tank.
The coil can be placed directly in the firebox, inside or outside it. Its shape can be very different, starting from the simplest U-shaped horseshoes, continuing with the already mentioned spirals with different numbers of turns, and ending with complex welded registers. The latter are done to increase reliability and reduce energy losses, but since they are large in size, they are usually placed in spacious heaters.
Rectangular tank on a pipe
This is another type - no longer an internal cylindrical container, but a structure consisting of an airtight body made of stainless steel.
The principle of operation remains the same - the heated liquid rises into the reservoir, the cooled liquid goes back. In implementation, a chimney with a diameter of Ф115mm (without the use of an adapter) or 110mm (with use) is suitable for it, and exhaust steam entering the room is almost excluded. True, the system must be sealed; it is important to replenish the structure with water in a timely manner.
Recommendations from experienced professionals
Here are some more tips on how to install a heat exchanger in a bathhouse as rationally as possible:
- If you do not plan to use a circulation pump, make the pipeline at a slope of 50 so that the liquid moves due to gravity.
- Do not take a tank that is too large and/or do not pour too much water into it, as it simply will not have time to reach a comfortable temperature in the time you need.
- Pay maximum attention to sealing - during assembly, do not hesitate to check the quality of each connection several times.
Choose durable materials and a suitable design, make the calculations correctly, and strictly follow the instructions and recommendations. A competent master knows how to make and connect a heat exchanger in a bathhouse, because correct installation will be the key to safe operation of the equipment, and therefore a comfortable bathing after the steam room.
Finally, a video about how the universal heat exchanger model works:
Video description
The video will show what a sauna stove with a heat exchanger is:
Siphon type
Quite effective, but not very popular method. A storage tank is installed at some elevation from the surface of the furnace. From its bottom, at an angle, a pipe with a sealed end goes into the hearth. In this case, you cannot do without boiling.
It starts at the end of a sealed pipe. The water turns into steam bubbles, which begin to rise to the top. In a cold environment, they burst and heat the surrounding water. Additional heating also occurs due to the usual convention of warm water rising to the surface and cold water taking its place.
