What is an RTL valve for a warm water floor, design, types and installation rules

One crucial part that you may have heard about when setting up a warm water floor system is the RTL valve. This small gadget is crucial to the smooth and effective operation of your floor heating system. However, what is an RTL valve precisely, and why is it so crucial? Let’s dissect it so you can comprehend its types, design, and correct installation.

The term "Return Temperature Limiting" (RTL) valve refers to a device that helps control the temperature of water returning from your floor heating system to the boiler. The valve keeps the heating system operating within ideal temperature ranges, preventing overheating and enhancing energy efficiency, by managing this return temperature. This is essential to keeping your floor’s temperature at a steady, comfortable level.

RTL valves come in a few varieties, each intended to meet particular requirements and configurations. While some are automatic and change based on the conditions in real time, others are manual and let you change the settings yourself. Knowing which kind best suits your system can have a significant impact on how well your floor heating works.

Although installing an RTL valve may seem difficult, it is doable with the correct advice. To guarantee correct installation, it’s critical to carefully follow the manufacturer’s instructions. Usually, this entails putting the valve in your floor heating circuit’s return pipe and making sure it’s calibrated properly to maintain the proper temperature.

All things considered, the RTL valve is a minor but essential part of your warm water floor system. Maintaining a controlled return temperature makes your home more comfortable by enhancing the effectiveness and efficiency of your heating system. The secret to getting the best results, whether you’re installing a new system or upgrading an old one, is to comprehend and install an RTL valve correctly.

What is it and why?

The RTL valve is a type of shut-off control valve used to regulate coolant temperature.

Ensuring proper circulation of coolant in the system is crucial for the efficient operation of an innovative floor and room heating system. There are two methods for regulating the water temperature in the underfloor heating pipeline: mixing and restricting water flows. Experts’ other recommendations are all hybrids built on these techniques.

Mixed-flow schemes have been mastered for a long time, and many experts advise using them. The flow-limiting method requires an alternative installation. When installing heated floors, a system with an RTL valve is utilized, as it was necessary to install a heating system at the time of construction when none existed.

When cutting the circuit into the line, an RTL valve is installed on the return line to stabilize the water temperature. In this instance, the valve will stop hot water from entering the loop until the return flow reaches the predetermined value, regardless of the temperature of the coolant that is supplied.

The valve has a maximum temperature setting of 50 0 C. If the temperature is higher than intended, the regulator will cut off the working medium’s flow. The valve is placed at the circuit’s outlet, and the floor loop is connected to the radiator riser.

When used?

The incoming water is sent straight to the pipeline by the RTL regulator, which does not mix it with the circuit. The temperature of the flows at the water circuits’ outlet is limited by the regulator’s valve. Hot water is delivered in portions when using such a heating system to prevent overheating of the floor.

The RTL design is a small, portable gadget. The return comb is put together using tees that have RTL taps installed; there is no pump with a mixing unit. Installing a separate system in a small space, like an apartment, is therefore advised. When there are few circuits, it is better to install a design that controls the return flow; installing a complete mixing unit with a pump is not beneficial in these situations.

Heating rooms using RTL underfloor heating that can be used in one or two 20 m 2 rooms with a valve. The floor will heat unevenly over a greater surface area.

General requirements for characteristics

The temperature of the returned coolant from a small underfloor heating system—roughly 15 m 2—is limited and controlled by a system with an RTL valve. During installation, you must ensure that the limiter’s temperature setting is not higher than the ambient temperature.

You must carefully consider the installation location because the valve will not open if you do not follow this requirement. Installing a temperature limiter close to the distribution circuit pipeline is not advised. Pipes are installed without fracturing or developing scale. Lubricants and oils shouldn’t be present in the coolant.

If the pipeline is installed 20 days after the screed, begin the test heating. Water that has been heated to 20–25 0 C should be added to the system and left there for three days. The highest computed temperature mode should then be set and held for four days. Overheating the pipeline’s maximum allowable temperature is not advised.

Operating principle:

• The reverse flow temperature limiter belongs to the automatic thermostatic control device.
• Temperature readings are sent to the sensor due to the conductivity of the liquid medium.
• RTL maintains the set temperature in accordance with the required proportionality.
• The valve opens when the temperature does not correspond to the set limit value.

The following table lists the RTL valve’s technical specifications:

Types of RTL

An illustration of the product will be provided by a picture of the Unibox RTL type regulator. The device comes with a thermostat and valve labeled "RTL," as well as a cover with a flywheel integrated to restrict the return flow’s temperature range.

The following components make up the kit:

• mounting box with thermostatic valve;
• built-in return flow temperature regulator;
• air release valve with water drain.

Technical details:

• installation depth – 60 mm.
• maximum pressure – 10 bar;
• operating temperature 20-100 0 C
• return flow adjustment range – 10-50 0 C.

It is possible to use the device in conjunction with radiators in a heating system.

The device is installed on a floor area of up to 20 m 2 and the regulator controls the heating level of the return flows. The thermostatic head sets the temperature within the specified range, and support is provided automatically.

Coolant is supplied in segments, flows around the heated floor’s entire circumference, and then passes through the regulator during the installation of the Unibox RTL limiter. If the water level is below the upper limit, the valve opens.

Pros Unibox RTL:

• the possibility of connecting a combined type circuit;
• selection of a circuit in accordance with specific conditions;
• no need for additional units that reduce the water temperature;
• ease of adjusting the floor heating.

Cons:

• the hot coolant must be supplied in uniform portions;
• the use of the regulator is possible only in small areas;
• serves a short loop length, only 50 m.

There are thermostatic heads of the RTL type for sale, which lowers the price of a comb designed for a country home up to 240 m 2. Because of this, installing a circulation pump won’t be necessary in this scenario, but the circuit’s length should still be within 60 meters. Connect a strong main pump to a floor that has loops made up of more than ten pieces and a lengthy supply line. Three-way valves for 100 m circuits are used in large homes.

When a warm floor’s hinges and a swinging mixing knot are connected to the collector, temperature limiters can be employed as balancing components. To regulate the water flow in each circuit, set the thermogol’s temperature based on the returned coolant calculation.

How the design works?

Assuming that RTL is adjusted by +30 0 s, the tap opens to take up the subsequent portion of coolant when the temperature drops by 1 degree.

Water circulates through the loop, and when the temperature in the node where the valve is installed rises to a certain point, it shuts off the flow, waits for the temperature to drop, and repeats the process.

Stable temperature maintenance throughout the pipeline’s circumference is essential for the warm floor to function effectively. The coolant is supplied at a high temperature as part of the structure’s RTL valve operation principle. There is a set quantity of hot fluid provided. After a few minutes, the coolant enters the loop and fills it, at which point the movement ceases.

Water transfers heat to the screed, which dissipates energy throughout the circuit’s volume after absorption and prevents the pipeline’s passing locations from becoming overheated. A fresh batch of hot liquid is added to the loop when it cools. You can maintain the floor in accordance with the installation thanks to the regulator’s uniform heat distribution. There are various temperature ranges in which it can be set. It is sufficient to use the regulating valve to lower the portion feed rate if a cooler circuit is required.

The design comprises a single-type RTL thermal head with a valve installed on the loop’s return.

The apparatus can be assembled into a single body that is mounted on a wall or niche with the lid visible. Liquid temperature is transferred by the contact of brass or copper cores in the RTL valve and thermal head.

It’s a pretty easy process. Once the circuit is filled to a predetermined temperature, the flow regulator opens as the liquid cools. After filling with hot water, it stops moving. Only the return line has the valve installed, and it only modifies the flow for a brief period of time (l/min).

Service life

The manufacturer determines the quality of all underfloor heating apparatus, parts, and components. Several well-known brands’ companies produce RTL valves:

• Schlosser;
• Honeywell;
• Fado.

High performance coolant temperature limiters with a five to ten year service life guarantee are produced by manufacturers. In actuality, the valve has a 15-year breakdown-free lifespan. A person’s service life is impacted by:

• correct installation of underfloor heating and installation of the RTL valve;
• regularity of preventive inspections;
• care of equipment and heated floors.

The RTL regulators are stable because of a straightforward operating principle.

How to choose correctly?

Consider three primary factors when selecting a coolant temperature regulator, apart from the brand of the manufacturer:

• area of ​​the room that will be heated by the underfloor heating;
• diameter of the pipes;
• capacity, the characteristic is set based on the design data of the floor arrangement.

A 2-way valve supplies coolant to the circuit when a small room (10 m2) is heated and the warm floor is not used as the primary heating system. Such a device maintains the desired temperature and automatically supplies hot water to the connected circuit in the necessary portions.

In order to control the flow and temperature of warm water underfloor heating systems, an RTL valve is essential. The definition of an RTL valve, its various varieties, and the best installation techniques are covered in this article. Through comprehension of these components, owners and constructors can guarantee dependable and effective underfloor heating, resulting in a cozy and uniformly heated area.

Best manufacturers

1920253 HERZ

Austria is the manufacturing nation. Warm floor regulator, RTL valve 1920123. Cost range: 4800–5100 rubles on average. They can be used with radiator heating and are used to control the temperature of coolant in an area of 15 m³ by throttling the liquid flow. No additional pump is needed. It will require adapters to make the connection. Important attributes are enumerated in the table:

Fado

Business Fado, originally from Italy. The Fado KLR01 is the model of the regulating valve used to limit the coolant temperature. With this device, you can design circuits for underfloor heating without the need for a comb. Included in the kit are:

• regulating valve;
• thermal head for regulating water temperature;
• mounting box;
• cover;
• fasteners.

Technical attributes:

• temperature adjustment range 20-60 0 C;
• distance between pipes – 60 mm;
• working pressure – 10 bar;
• valve capacity with a coefficient = 1.06 m3 / hour.

There is a five-year warranty from the manufacturer.

Schlosser Kombi with a Brilliant thermal head

High-quality limiters are made by a Polish company and sold under the Schlosser brand. The Schlosser Kombi RTL kit, which has an RTL valve (G3/4) and a Brilliant White thermal head, is one example.

The apparatus concurrently controls the ambient temperature and coolant temperature for underfloor heating systems with a surface area of S=20 m^2. gives a circuit with a length of 100 meters; the pipes’ diameter must be 12 mm. intended to heat the floor covering to a maximum of +50°C. 14,000 rubles is the average price of similar products.

Honeywell

A big German company owns the Honeywell brand. The manufacturer makes sure that homes are comfortable with its products. The underfloor heating regulator Honeywell RTL-UNIBOX. 4,000–5,044 rubles is the price of the valve. The regulator, which is used in underfloor heating systems, is made to restrict the temperature in the return, with a heating range of 20 to 50 0 C.

Oventrop

Germany is the origin country and the manufacturer’s brand is Oventrop. The company manufactures top-notch underfloor heating arrangement products. especially the RTL thermostat from Unibox. The limiter’s purpose is to control the return flow’s temperature. Technical details: The product costs between 10,000 and 11,000 rubles on average.

Features of schemes

Although the method for setting up a warm floor with an RTL valve is quite straightforward, it is capable of controlling the heating of reverse flows. A mixing unit for a few loops does not need to be installed in the hallway if the home’s owner only needs to heat one room, for example. Using the radiator scheme, cut the contour into the ruler. SHOULD REQUIRE thermal godresses as well as card care. The only component required to modify the return water’s temperature is the RTL valve. Without a pump, the valve will have to operate on coolant.

The limiter will not open the coolant’s capacity into the loop until the fluid reaches the specified value on the device’s body, regardless of the temperature at which the water in the radiator system is heated. Advantages of the plan:

• simple installation and adjustment;
• energy independence;
• you can regulate the temperature from the room where the circuit is installed;
• the ability to service 2 circuits (or more) without mixing units;
• an air vent with a valve is placed in the housing.

Minus in short circuit length underfloor heating.

Installation rules

At the underfloor heating system loop’s outlet, the RTL valve is installed. The thermostat sensor expands in response to an increase in return line temperature, which influences the valve and causes it to close.

The return spring opens the valve when the temperature drops and compresses the sensor. Rotate the element’s upper portion to adjust the regulator. For adjusting the coolant temperature, it has a scale. Lift the lock up to block the current temperature mode size setting and set a new one. Verify the configuration by turning the product’s upper section.

Rules and technology for connecting to the system

Use threaded connections to join the RTL valve to the pipeline. The rationale behind using sealing materials Flax fiber impregnated with a substance is known as FUM tape. To prevent any protrusion, the products are positioned on the thread’s surface.

Following assembly and while in use, loads from pipes in the following forms shouldn’t occur in this unit:

• bends;
• distortions;
• torsion;
• sprains;
• vibrations;
• uneven tightening of fasteners.

Install any kind of expansion joints or supporting components that can lower the amount of stress placed on the joints if necessary.

The system needs to be built to deliver the necessary coolant temperature. The heated floor is harmed by overheating.

Exploitation

The guidelines for maintaining the limit valve are the same as those for maintaining the entire underfloor heating system. If necessary, a preventive inspection can help ensure that repair work is completed on time. Cleaning the valve itself while it is in use is necessary to stop the moving parts from oxidizing. One turn of the operating range handle every thirty days is sufficient.

How to avoid mistakes?

As long as the warm floor is installed correctly and all installation requirements are met, there shouldn’t be any problems installing the RTL valve. Manufacturers typically provide detailed packaging recommendations. If they overlooked something when installing the valve, that would have been a mistake.

• the area of ​​the room;
• the number of circuits;
• the capacity of the pipeline;
• the quality of the coolant;
• the cross-section of the pipes;
• the valve is not installed on the return.

Planning should take into account every structural component of the warm floor.

Advantages and disadvantages

Installing an RTL valve is a big benefit for small rooms because it eliminates the need to buy a pump and set up a mixing unit. Particular benefits are worth mentioning:

• simple installation, even a person without special skills can handle it;
• no need to do complex calculations for adjustment;
• easy adjustment;
• excellent scalability.

Minus in terms of volumes. is only installed in rooms up to 20 m2 and serves a small length circuit valve. Furthermore, using such a connection with a system that has a high hydraulic resistance is challenging.

Useful video

Regarding the valve’s characteristics in the video:

What is an RTL Valve?	An RTL valve is a device used in underfloor heating systems to regulate the flow of warm water through the pipes. It ensures that the water is evenly distributed, maintaining a consistent temperature throughout the floor.
Design	The RTL valve typically consists of a control unit that adjusts the water flow and a thermal actuator that responds to temperature changes. It usually includes a flow meter and a temperature sensor to monitor and control the system effectively.
Types	There are several types of RTL valves, including manual and automatic valves. Manual valves require you to adjust the flow manually, while automatic valves use sensors and controllers to adjust the flow based on the temperature readings.
Installation Rules	When installing an RTL valve, ensure it is positioned correctly in the pipework, following the manufacturer"s guidelines. It should be easily accessible for maintenance. Proper insulation around the valve is also important to prevent heat loss and ensure efficient operation.

In conclusion, an RTL valve is essential for controlling the water’s flow and temperature in underfloor heating systems. Its layout guarantees that the heat is dispersed equally over the floor, giving your room a constant, cozy temperature. The RTL valve maximizes energy efficiency while assisting in maintaining the appropriate temperature by regulating the flow of water.

RTL valves come in a variety of forms, each intended to satisfy particular requirements and tastes. Whether you go with an automatic or manual valve, it’s important to make sure it meets the needs of your system. While automatic valves can add a layer of convenience and efficiency by adjusting the flow based on temperature changes, manual valves provide simple control.

The efficient functioning of RTL valves depends on proper installation. Make sure they are installed in accordance with the system’s specifications and the manufacturer’s instructions. This will assist in avoiding problems like inconsistent heating or decreased effectiveness. Maintaining optimal performance of your RTL valve can also be ensured by routine maintenance and inspections.

Your underfloor heating system will function better overall if you purchase a high-quality RTL valve and follow the right installation and maintenance procedures. This prolongs the life of the system overall and saves energy in addition to increasing comfort.

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