How to check the expansion heating tank

There’s more to keeping your house warm and comfortable all year round than just cranking up the thermostat. It’s critical to maintain your heating system properly, and one important part to watch out for is the expansion heating tank. This crucial—though frequently disregarded—component of your heating system aids in pressure regulation, promoting effective operation, and guarding against damage. Maintaining a comfortable home and a functional heating system depends on knowing how to inspect and care for your expansion heating tank.

A closed-loop heating system’s expansion heating tank is essential. Water expands when it gets hotter, adding pressure to the system. In the event that this expansion is not accommodated, the pressure may build to potentially hazardous levels, which could result in leaks, component damage, or even system failure. By absorbing excess pressure and offering a secure outlet for the expanded water, the expansion tank serves as a buffer. To make sure this component keeps working properly, regular inspections and maintenance are necessary.

Making sure your expansion heating tank is appropriately pressurized is one of the main reasons to inspect it. The tank’s internal air bladder may eventually lose pressure, making it less effective in absorbing excessive water expansion. Reduced efficiency and elevated system pressure may result from this. A pressure gauge can be used to perform the easy task of checking the expansion tank’s pressure. For best results, make sure the pressure is as high as specified by the manufacturer.

It’s crucial to routinely check the expansion tank’s general condition in addition to performing pressure checks. Keep an eye out for any indications of leaks, corrosion, or damage to the tank’s parts. Any anomalies should be dealt with right away to avoid more problems. Furthermore, look for any indications of deterioration or leaks at the tank’s connection to the heating system. Early problem detection can save expensive repairs and system downtime.

It is possible to guarantee that your heating system runs effectively and efficiently by taking the time to inspect and maintain your expansion heater. Frequent pressure checks and inspections can aid in the early detection of problems, enabling prompt repairs and averting possible system damage. Your expansion heating tank can sustain the heating needs of your house for many years to come with the right maintenance.

What is the pressure in the expansion heating tank about

Closed-off tank

The expansion tank is an example of auxiliary equipment, but the heating system cannot function effectively without it. You must select the appropriate option and configure the parameters of each component of the network for it to operate properly. The expansion tank’s pressure is one of the most crucial indicators.

Why is this design needed?

It is necessary to address the types and principles of operation of this equipment before discussing the functions and configuration of an expansion tank. Why is a design like this required for the heating system? The device’s primary function is to adjust the network for thermal expansion. It is true that the coolant’s density and volume change with heating and cooling.

Because heated water has a tendency to increase in volume and affect pipe and radiator walls, it is important to install this device in the engineering network. The system can easily burst in the event of a significant rise in water pressure. You can save the boiler in addition to the pipeline by installing the expander. Ultimately, his initial calculations are based on a specific water pressure within the system.

The volume of expansion devices varies. It is important to keep in mind that the volume of this element should be at least 10% of the total volume of coolant circulating in the system when selecting a model appropriate for the technical parameters of a given network. The volume is summed up in the boiler, pipes, and radiators for this computation. Finding the volume is simplest when the system is being pumped. It is best to choose a model with a small margin, but keep in mind that the volume that comprises 10% is a minimum.

It is appropriate to discuss wall gas boiler expansion containers separately. The majority of contemporary wall-mounted models come with an integrated device that is mounted on the side or back wall and has nipples. The nipple aids in increasing pressure.

Device and principle of operation

Every kind of expansion tank has the same component. The metal case has two hooked compartments inside. The nipple and the neck for the pipeline connection are located on opposite sides of the body. Inside the case is a diaphragm. It will take up the majority of the volume in an empty container, with the remaining area being filled with air.

The coolant heats up, expands in volume, and seeps into the space between the diaphragm and the case when the system is operating. As the system’s water temperature drops, so does its volume, and the pumped air forces the water back into the pipeline.

Installation of an expansion element

Equipment for boilers is made to function at a specific pressure. This implies that a specific pressure is also necessary for the expansion tank to function normally. Air or nitrogen, which filled the case, supports it. At the factory, the container is circulated. It’s important to make sure the air doesn’t leak during installation. The gadget won’t be able to operate otherwise.

A pressure gauge is used to keep track of the pressure. The device’s running hand indicates that the expander’s air has been released. Since air can be pumped through the nipple, this condition is generally not a major concern. The tank’s average water pressure is 1.5 atm. However, they might not be appropriate for a particular system. In this situation, the pressure needs to be changed on its own.

Indicators that are normal: 0.2 atm lower than the system. Exceeding the pressure in the expansion capacity in relation to this network indicator is prohibited. Under such circumstances, the increased volume of coolant will not be able to enter the tank. Through the joining size, the tank and pipeline are connected.

It’s crucial to install the expansion tank in the proper location in addition to making the proper connections. Installing this system element on the return between the boiler and the pump is advised by experts, even though contemporary models can be mounted anywhere.

A ball valve is installed on the pipe that connects the extensor capacity to guarantee the structural integrity of the pipe. Shut-off valves will remove malfunctioning equipment without requiring the coolant to be pumped out of the system. The crane needs to be open for the system to function. If not, pressure inside it will build up and it will leak at its most vulnerable point.

Boiler room installation

Other kinds of tanks are installed in open systems where the coolant circulates naturally. An open reservoir of this kind is typically made of sheet steel. It must be installed at the engineering network’s highest point.

Such an element operates on a very basic principle. The liquid rises along the pipes with the air as its volume increases, pushing it out of them. After cooling, the natural air pressure and gravitational forces cause the coolant to return to the pipeline.

Why pressure drops?

Although the expansion capacity’s pressure should always be high, it occasionally drops while the system is operating.

The pressure may drop for a number of reasons:

  • The leaks of the coolant. Most often, a similar problem occurs in systems where it is not water that is used as a coolant, but an antifreeze. Such liquids can penetrate into the smallest cracks, causing leaks. In this case, it is necessary to eliminate the leak and fill the tank with air.
  • Pressure in the boiler. With a significant decrease in indicators, it is necessary to contact specialists. If the pressure decreases slightly and is aligned after starting the system, it can be operated, since such malfunctions do not cause damage.

Pressure setting

One parameter that can be adjusted in the heating system is the water pressure in the expansion element. Everything can be done on its own, and the setup is fairly straightforward.

The following must be configured in order to set the required parameters:

  • Make a calculation and determine the required indicators – by 0.2 atm. less than in the system.
  • Install these indicators before the installation of the tank in the system by dropping air or pumping it through the nipple.
  • Connect the container to the pipeline and fill the system with water. You need to do this slowly, tracking pressure indicators in pipes and tank. Roll the coolant until the pressure indicators are equal.
  • After that, you need to connect the pumping equipment and continue the rolling of the coolant. You need to pump water until the moment when the operational pressure is reached in the tank, calculated before the installation of the network. This will ensure that the reserve volume of water enters the housing.
  • The first inclusion of the system should be carried out in the maximum temperature mode. In this condition, the volume of the coolant increases by the value of the specific increment. This provides the amount of water equal to its capacity. The pressure in the tank rises to maximum indicators.


The expansion tank is the most crucial extra component of any heating system. Industrial models must be installed for complex closed systems, even if installing a basic open tank at the top suffices for open systems with gravitational circulation.

These are not loose tanks. Air is pumped into the housing during the production process to keep it at the pressure required for forced circulation systems to operate normally. With a pressure gauge and a regular car compressor, you can set up the required pressure indicators on your own.

Expansion tank for heating systems

One of a private home’s most vital life support systems, heating is crucial to its steady operation. Pressure is one of the variables that needs to be kept an eye on. If it’s too low, the boiler won’t operate; if it’s too high, the equipment is high. There must be an expansion tank for heating in order to maintain system pressure. The gadget is basic, but without it, heating won’t function for a while.

What is the expansion tank for heating

The coolant frequently heats up and then cools down when the heating system is running. Transparent operations, as the fluid’s volume fluctuates. It either rises or falls. Simply replace the excess heat carriers in an expansion tank. Therefore, this device’s function is to adjust for variations in coolant volume.

The expansion tank’s heating principle of operation

Types and device

The two types of water heating systems are closed and open. The circulation pump in a closed system is responsible for providing coolant circulation. He just forces water through the pipes at a certain speed without applying any more pressure. An expansion tank is used in this type of heating system to heat closed objects. Because it is a sealed container split into two sections by an elastic membrane, it is known as closed. One component contains air, while the other replaces any extra heat carrier. The tank is also known as a membrane because of its presence.

The absence of a circulation pump in an open heating system does not provide. Here, any container—at the very least, a bucket—to which heating pipes are connected serves as the expansion tank for the heating system. Although it can be, he doesn’t even need a cover.

In its most basic form, it is a metal container that is placed in the attic. There is a major disadvantage with this option. Coolant evaporation occurs in non-monthly tanks, so constant monitoring and addition are required. This can be manually completed from a bucket. This is inconvenient because there’s a chance you won’t remember to refill water supplies. This raises the possibility that the system may become irate and malfunction.

Water level control that is automated is more practical. Indeed, in the event that the tank overflows, you will still need to disconnect the water supply and remove the overflow hose (pipe) from somewhere in the attic in addition to the heating pipes. However, there is no longer a need to check the coolant level on a regular basis.

Calculation of volume

The volume of the expansion tank for heating can be found using the following very easy method: The calculation is 10% of the system’s coolant volume. It was something you ought to have calculated when creating the project. In the event that this data is incorrect, you can calculate the volume experimentally by pouring in fresh coolant while simultaneously measuring the old one (letting it pass through the counter). Compute is the second route. Calculate the system’s pipe volume and then add the radiator volume. This represents the heating system’s volume. Ten percent of this figure is found here.

The shape may vary.

Using the formula is the second method to figure out the expansion tank’s volume for heating. In this case as well, the system’s volume (represented by the letter C) is necessary, but additional information is also required:

  • maximum PMAX pressure in which the system can operate (usually the maximum boiler pressure is taken);
  • The initial Pinin pressure – from which the system begins work (this is pressure in the expansion tank, is indicated in the passport);
  • The coefficient of expansion of the coolant E (for water 0.04 or 0.05, for antifreeze is indicated on the label, but usually within 0.1-0.13);

With all of these numbers, we use the following formula to determine the precise volume of the heating system’s expansion tank:

Formula for figuring out the heating expansion tank’s volume

Although the calculations are simple, is it really worth messing with them? No, if the open-type system is clear-cut. In addition to being independent, the cost of the container is not significantly influenced by the volume.

For closed heating, expressive tanks need to be computed. Their pricing is heavily volume-dependent. However, in this instance, it is preferable to err on the side of caution because the system will deteriorate or possibly fail quickly due to insufficient volume.

Place the second expansion tank if the boiler has one but its capacitance is insufficient for your system. They should provide the necessary volume overall (the installation is the same).

What will the insufficient volume of the expansion tank lead

The coolant expands when heated, and any excess expands to fill an expansion tank. The excess is drawn through the emergency discharge valve if it does not all fit. In other words, the coolant enters the sewer.

The graphic image’s working principle

Then, when the temperature decreases, the volume of the coolant decreases. But since it is already less in the system than it was, the pressure in the system drops. If the lack of volume is slight, such a decrease can be uncritical, but if it is too small, the boiler may not work. This equipment has a lower pressure limit at which it is efficient. When the lower limit is reached, the equipment is blocked. If you are at home at this time, you can correct the situation by adding a coolant. If you are not, the system may defrost. By the way, work at the limit also does not lead to anything good – the equipment quickly fails. Therefore, it is better to play it back slightly and take a slightly larger volume.

Pressure in the tank

Which pressure should be set on the expander is indicated by certain boilers (usually in gas) in the passport. In the event that no such record exists, the system’s working pressure should be 0.2–0.3 atm lower in the tank.

A low-rise private home’s heating system typically runs between 1.5 and 1.8 atm. The tank should therefore have between 1.2 and 1.6 atm. The standard pressure gauge, which is attached to the nipple, which is situated in the upper region of the capacity, is used to measure the pressure. A plastic cover conceals the nipple; remove it to reveal the spool. You could also experience too much pressure from it. Operating on the same principle as an automobile spool, you are pulling air to the required indicators by bending a thin plate.

Where the pumping nipple is situated

The expansion tank’s pressure can also be raised. You will need a car pump with a pressure gauge to accomplish this. Attach it to the nipple and pump it to the required levels.

The tank is disconnected from the system and all of the aforementioned procedures are performed on it. It is not required to remove it if it is already installed. The pressure in the heating system’s expansion tank can be immediately checked. Just exercise caution! When the boiler’s coolant is drained and the system is not operating, check and modify the expansion tank’s pressure for heating. It’s critical that the boiler’s pressure is at zero for accurate measurements and tank tuning. As a result, we carefully lower the water. After that, we connect the pressure gauge to the pump and modify the settings.

Where to put in the system

In a closed system, the expansion tank is positioned to create a stream in the opposite direction, that is, after the boiler and before the pump. Consequently, the system operates with greater dependability. Therefore, where you have a circulation pump determines the precise installation location.

The expansion tank installation diagram for the heating

Through the tee, it is linked to the system. Cut the tee into the pipe, wind the tank on it, and direct the output that is perpendicular up. You will have to bend over if the wall prevents you from placing the container, but the tank is elevated. Assuming the expansion tank is installed at this point.

An illustration of a crane installation

However, it is advisable to place another tee after the tank, which is free to set the shut-off crane, for ease of checking. This cuts off the membrane tank, allowing for inspection without completely emptying the system. Pull water from the boiler so that it overlaps the tap. Verify the pressure in the boiler’s disconnected branch. It ought to be zero. Work on other settings can be completed after that.

Pressure in the expansion tank of a closed -type heating: instructions, principle of operation

January 18, 2016

Physics students are taught that when a liquid is heated, it expands within its volume. Pressure rises quickly in heating systems because the pipes’ elasticity isn’t high enough to support a larger volume. This frequently results in highways and radiators rupturing. The entire system may fail in a matter of hours if you are unable to remove the extra water volume. To do this, extra communications are installed in order to build up pressure inside the closed-type heating system’s expansion tank.

Principle of operation

This auxiliary equipment is necessary for the room’s heating system to function normally. The most basic devices allow one to prevent the water jacket and account for the heated fluid’s expansion. Because of this, it’s important to abide by the safety guidelines when using. Selecting the required unit and installing it are fairly easy tasks. The long-term stable operation of the entire heating system will be ensured with the appropriate equipment selection.

Selection of a tank

It will be necessary for all to rationally select and install such a tank when building a trustworthy heating system. The functions utilized and the installed design type will determine the device’s characteristics. There are just three viable options on the market.

Expressive closed-type heating tank. Depending on the needed volume, the price of these units in the domestic market can range from 2500 to 75,000 rubles. Air is poured into a standard sealed tank. A rise in system pressure causes the air to compress, filling the tank’s capacity. The interior of the container is fitted with a unique membrane. After mixing with oxygen to increase the corrosion activity of water, the aggregate must be protected from rust.

An open tank lacks a sealed cover. In the home market, the average price is roughly 3,000 rubles. These devices are employed not only to offset system expansion but also to remove air traffic congestion. Through the use of a tank like this, coolant can be added to the design to offset its slow evaporation.

A tank with an upper outlet can be used in the design of the house’s water heating system. This is a valve-equipped sealed container. You can stir the water in your home heating system the fastest by using a tank like this one.

Installation instructions

The best possible operation of heating devices requires that expansion tanks be installed strictly in accordance with technology. In order to make it easier to drain the coolant in the event that the membrane breaks, the device must be mounted above the boiler with the water pipes pointing downward.

Pumps for circulation should be used to counteract the forced circulation of energy carriers in such a system. Compared to other types of devices, installing and selecting a flat expansion tank for a closed-type heating system is far more challenging because these tanks are not made to account for temperature expansion. The quality of the installation will determine how steadily the entire system operates.

These tanks are situated in regions where coolant does not twist. This makes the choice to place the circulation pumps in front of straight pipeline sections the right one. You will need to become acquainted with some general guidelines that must be followed when planning and putting the system together regarding the choice and placement of tanks.

Calculation of volume

The coolant in the tank should make up one-tenth of the total coolant flowing through the system. It is not possible to select the smaller size in any scenario because the closed-type heating’s expansion tank will experience excessive pressure, making it impossible to stop a hydraulic explosion. Only in situations where water is used as a coolant is this computation appropriate. Should the system be circulated with ethylene glycol, you should select a container with a larger capacity.

Such an expansion tank needs to have a unique safety valve installed. He enters the factory kit almost every time. If the tank does not come with a valve, you will need to purchase and install one. This device has the ability to lower the pressure within the expansion tank of the closed-type heating system.

You can purchase another unit if the calculation was done incorrectly and an insufficiently large unit was bought. An obvious indicator of a tank selection error in heating systems is a persistent rise in pressure.


At the same time, the height of the tank installation above the floor will have no bearing whatsoever. By using specific valves, tightness will be preserved and air will be expelled. It is advisable to consider that the best option for coolant flow during installation will be from above. This allows the air that is entering the fluid department to be removed.

When choosing a расширительный бачок for a particular type of photography, the effect on the entire system may be significant, if one compares it to the option of purchasing two types of контурных электрических или газовых котлов, wherein механизм для давления уже предусмотрен.

A suitable amount of water

The size of the room, the boiler’s power, and the quantity of heating elements all affect how much water is needed for heating systems. In traditional systems, 14 liters are computed for every 1 kW of voltage. A quantity like this ought to be sufficient for appropriate circulation and heat exchange.

Calculation methods

Selecting an appropriate expansion tank for a closed-type heating system is not always simple. There are situations when following the instructions for installing the building’s heating system is impossible without outside assistance. Any owner can select an appropriate tank in a number of reasonably priced ways. The simplest method is to look for a specialized online calculator program that makes it easier to calculate using the specified parameters and figure out how big of a container is needed to fully compensate for the excess pressure in the system.

You can also discuss this matter with experts employed by the design bureau. This is the most expensive but most dependable choice. This method helps you design it correctly and get it ready for long-term, stable operation.

Some attempt to determine the required tank volume by hand using the formulas. The amount that the pressure in the closed-type heating system’s expansion tank can fluctuate must be considered. At 95 degrees Celsius, the coolant temperature increases by 0.04 and at 85 degrees Celsius, it increases by 0.034. Through specialized programs, calculations based on the system’s total water volume determined by the heating boilers’ power can be carried out.

Precise computations ascertain the overall heating efficiency, guaranteeing continuous operation and ruling out potential equipment malfunctions or violations.

Recommendations of specialists

The closed-type heating system’s expansion tank’s maximum allowable pressure is dictated by the safety valves’ threshold values. It is preferable that they are modifiable. Tank capacities are first chosen with a buffer in order to ensure that they can fulfill all required duties even in the event that computation errors occur without causing mishaps. It is best to hire professionals to install all equipment, so don’t skimp on the cost of purchase.

Remember that the heating system’s dependability will determine how safe your home is from the cold, as any malfunctions could render the building completely without heat. Many issues can be avoided with proper installation, and any house will be protected even in the worst cold. Every closed-type expansion tank for heating has the potential to deteriorate with time. There are occasionally issues with the heating system’s operation. Seeking professional assistance is the best way to ensure that all issues are resolved.

A membrane tank for heating closed type

Rubber dividers separate this kind of apparatus. First pressure is provided by pumping air to the top of them. After the lower section receives coolant, the heating installation is started. The amount of water increases as the temperature rises, and any extra is released into the tank. An automatic pressure adjustment takes place in the heating system when the coolant is filled to its initial volume. The membrane assumes its customary orientation.

Tanks with the installation of the cylinder

Accurate pressure regulation is made possible by such apparatus. There is an air chamber all the way around the tank. When coolant enters the rubber compartment, it swells. These membranes’ primary characteristic is their replaceability in the event of wear. Sanitary standards and particular requirements for elasticity, heat resistance, possible operating duration, and moisture resistance should always be followed by rubber material.

Signs of Leakage Inspect for any visible signs of leaks such as water stains or puddles around the tank.
Pressure Gauge Check the pressure gauge on the tank to ensure it"s within the recommended range.
Expansion Valve Test the expansion valve to see if it releases excess pressure properly.
Condensation Look for any condensation on the tank, which could indicate a leak or a faulty valve.

An essential part of keeping your home’s heating system safe and effective is checking the expansion heating tank. It guarantees that the tank is operating correctly and has the capacity to handle any variations in water volume brought on by heating. You can do this check yourself and prevent future problems by following a few easy steps.

Locate the expansion heating tank first, which is usually located close to the hot water cylinder or boiler. It appears to be a tiny, cylindrical tank with pipes connecting it to the heating system. Check the pressure gauge that is affixed to the tank after you’ve located it. When the system is cold, this gauge, which shows the pressure inside the tank, should normally read between 12 and 15 psi.

The tank may need to be refilled with air if the pressure gauge reads less than 12 psi. This can be accomplished by turning off the heating system and letting it cool fully. Next, find the air valve on the tank’s top, and check the pressure with a tire pressure gauge. If it isn’t at the recommended level, add air with a compressor or bicycle pump until the pressure is within the proper range.

However, if the pressure gauge registers at more than 15 psi, there may be a problem with the heating system, such as an overcharged tank. It is best to seek the advice of a qualified technician in this situation so they can evaluate the damage and perform any required repairs. Ignoring high pressure levels may result in safety risks, leaks, or harm to the heating system.

As part of routine home maintenance, checking the expansion heating tank on a regular basis can help avoid expensive repairs and guarantee smooth functioning. You can keep your house safe and comfortable all year long with dependable heating if you become familiar with the procedure and take quick care of any problems.

In ensuring the efficiency of your home"s heating system, checking the expansion heating tank is crucial. The expansion tank plays a vital role in maintaining proper pressure levels within the heating system, preventing damage and ensuring smooth operation. To check the expansion tank, start by turning off the heating system and allowing it to cool down. Then, locate the expansion tank, usually near the boiler. Check the pressure gauge on the tank to ensure it falls within the recommended range. If the pressure is too high or too low, it could indicate a problem with the tank or the overall heating system. Additionally, inspect the tank for any signs of corrosion, leaks, or damage, as these could also affect its performance. Regularly checking the expansion tank helps to ensure your heating system operates efficiently, keeping your home warm and comfortable throughout the year.

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