Radiators And Convectors For Underfloor Heating

2023 Author: Douglas Hoggarth | [email protected]. Last modified: 2023-05-24 11:23

• Why build in floor heaters
• Varieties of floor convectors
• Application area
• Difficulties in the hydraulic connection
• Embedding technique
• Maintenance and repair

Why build in floor heaters

Due to the structural and architectural features, not every building allows the installation of wall heaters on enclosing structures. The main restrictions are dictated by:

1. Material of the walls and their thickness sufficient for reliable surface mounting.
2. Communication wiring diagram.
3. The need for a continuous finish from ceiling to floor.

Besides solving purely technical problems, there are also more practical aspects. This is, first of all, the invisibility of the heating system. The main advantage of floor convectors over underfloor heating systems is their high power, which makes it possible to compensate for even very significant heat losses.

The heat distribution scheme for floor convectors also compares favorably with wall convectors. A cold unheated zone does not form near the floor, while the temperature rise with the ascent of hot air is less pronounced. Convectors built into the floor are very easy to use, but for their installation you will have to invest a large amount of funds in the engineering support of the building.

Varieties of floor convectors

The cost of floor convectors is much higher in comparison with other heating devices. The only exception is split systems on air pumps, which, by the way, are also used in floor heaters.

How much do you have to pay for a floor heater? The price depends on a number of criteria:

1. Convector dimensions.
2. Its power density, that is, heat transfer per 1 running meter. m.
3. Thermostatic control method.
4. The presence of an air blower.
5. Workmanship and country of origin.

Floor convector design: 1 - grate; 2 - protective cover of the connection chamber; 3 - tangential fans; 4 - electrical connection block; 5 - fasteners; 6 - heat exchanger; 7 - convector body; 8 - connecting pipes; 9 - holes for connection

With the help of convectors in the floor, it is possible to create a thermal curtain of practically unlimited length, although individual sections, with rare exceptions, do not exceed 3 meters in length. On average, convectors occupy about 200 mm in width without forced airflow and about 300–400 mm if available.

The specific heat transfer of floor convectors ranges from 0.3 to 1 kW per linear meter. In terms of cost, each kilowatt of power is equivalent to an amount of 10-15 thousand rubles for domestic products and from 30 thousand rubles for imported equipment. The presence of forced airflow does not significantly increase the cost, but it significantly increases heat transfer.

For ease of use, floor-mounted convectors can be equipped with automatic regulators of the flow rate and air exchange rate, although most ordinary models are simply equipped with shut-off or control valves. There is also a difference in the source of heat for heating the air, it can be the coolant of the water heating system or electricity. In the latter case, temperature regulation can be carried out both by cutoff and by automatic power adjustment to the current operating mode.

Application area

The most obvious setting, where there are practically no alternatives for floor convectors, is the need to heat large glazing fronts adjacent to the floor of the room. Even a 20-30 cm parapet under the glass showcase would have made it possible to install much cheaper wall-mounting fixtures.

In this case, underfloor heating systems do not really help to solve the problem, because any glazing is several times inferior to capital fences in terms of resistance to heat transfer. Thanks to floor convectors, it is possible to organize an effective intake of cold air from under a window or door, heat it up and distribute it throughout the habitable volume of the room. There are, however, floor convectors that take air from the street, their use must be coordinated with the ventilation mode.

Convectors recessed into the floor are also very useful in organizing a thermal curtain opposite doors leading to open terraces and other spaces connected to the street. In such cases, the main calculation is not to compensate for heat loss, but to make the entrance of people into the room more comfortable.

If desired and appropriate financial possibilities, all other heating devices can be replaced with floor convectors. The devices we are considering do not generate extreme temperatures in the direct contact zone, and therefore, even for leather furniture installed in the immediate vicinity, optimal operating conditions are maintained.

Difficulties in the hydraulic connection

If the installation of electric convectors is limited to their neat installation into the floor and adjoining the floor covering, then for exchangers on a liquid heat carrier, the connection diagram to the heating system should be properly organized.

The tie-in point of the pipelines supplying the convectors should be as close as possible to the boiler or to the inlet of the hot coolant into the apartment. The permissible operating temperature of most convectors is slightly above 100 ° C. Almost all types of equipment are capable of operating when connected to centralized heating systems with a working pressure of up to 10 atm (with a building height of up to 9-12 floors). For systems with a higher water column, devices that can withstand up to 14-16 atm should be used.

The convector is connected to the prepared pipe outlets entirely inside the installation box. Accordingly, the length of the bends should allow pressing the connecting fittings for connection, plus a small margin. Most floor convectors are supplied with small bellows hoses, eliminating the need to fine-tune the length of the bends. There are also tee or straight threaded connections designed to connect convectors both in a parallel bundle, and separately.

All piping of the heat exchanger, provided by the manufacturer and the functionality of the device, is assembled at the factory. The convector can already have a built-in air bleed valve, flow regulator or electrically operated valve, but they can also be installed during the connection process. If necessary, the convector can be supplemented with shut-off or control valves - there is enough space inside the box for this. For more convenient use, flow-through thermostats can be taken out to the manifold unit, but only if each convector is connected to it with a separate pair of pipes.

Embedding technique

The installation of the convector can be carried out at the stage of pouring the concrete base of the floor. Included with many devices are protective covers that maintain the tightness of the technical box during concrete work. It is enough just to wrap the convector in a thin heat-insulating material, which will provide heat cut-off and facilitate dismantling in case of repair or replacement.

A more technological way of embedding is the advance arrangement of a niche, obviously larger in size than the body of the heater. In this case, it is much easier to align the convector along the plane of the floor covering and orient it relative to walls or other stationary objects. For the correct positioning, there are adjusting feet and a system of attachment to the base of the floor, anticipating the ascent or displacement of the box when it is bricked up.

An additional advantage of the latter method of embedding is the use of cement mortar with a fine porous filler, which helps to reduce heat leakage. This is especially important if no heating system is installed on adjacent floor areas. After fastening to the base and filling the gaps with a mixture with a liquid consistency, the protective covers and spacers are dismantled, which keep the walls of the body from being squeezed.

At the final stage, the pipe outlets are trimmed and the convector is connected to the general system. The upper edge of the box in most of the models is represented by a decorative corner, which provides easy installation of the protective grill and aesthetic adjoining to the floor finish without the use of end sills.

Maintenance and repair

During operation, convectors collect a fairly large amount of dust, which is abundant in the lower area of the room, from where air is taken. To prevent this dust from spreading throughout the heated space, high-quality convectors are equipped with air filters and dust traps. Their cleaning forms the basis of the convector's maintenance; adjustment and performance tuning are carried out a little less often.

The heat exchanger for floor-mounted convectors is made of high quality materials with a polished inner surface, on which no solid impurities build up. When flushing the heating system, it is recommended to disconnect the device from the system, and short-circuit the supply pipes.

Most representatives of this type of heating technology, especially foreign production, have a modular device. If necessary, any part can be safely dismantled and returned to its place, which is very convenient, for example, if the blower or control system is out of order.