Water pump for heating: types, characteristics, how to choose

Gravitational natural phenomena is not always able to provide a sufficient level of circulating coolant, especially in complex multiple ring systems. Will help drive traffic coolant water pump for space heating. That it represents the equipment? This question will be discussed in our article.

In addition the water pump device and Performance analyze species, particularly labeling. Also, a closer look at the advantages of circulating equipment and the important parameters to consider when choosing.

The general structure of the water pump

The water pump is integrated in the heating circuit for coolant flow. Therefore, such a system is called a heating

forced circulation.

It consists of the following basic elements:

• housing a working chamber;
• engine;
• impeller;
• screw for venting;
• terminal box.

The terminal box may be equipped with additional mechanical and electronic equipment, intended for controlling engine operation mode.

The simplicity of the device provides a high reliability of pumps, thanks to which they can operate effectively about 5-10 years.

Types of pumps for heating systems

Modern circulating pumps are divided into two basic types: "dry" and "wet". They are somewhat different internal arrangement and circuit operation, but the movement of fluid in them is still provided by the circulation processes in the system. Some models are equipped with devices for the automatic control of their work.

Option # 1 - devices "dry" type

Construction dry circulation pump coolant does not imply contact with the rotor. His work area is separated from the motor parts special rings.

They are made from the following material types:

• graphite;
• ceramics;
• tungsten carbide;
• of stainless steel;
• alumina.

The operating principle of the "dry" pump wheel is in rotation in the coolant medium. Water feeding hole located at the center of the main chamber and the tapping channel system - at the periphery.

The rotation of the impeller wheel function gives rise to centrifugal forces which move the heat transfer fluid from the body center to the edges. Such principle of operation of the circulation pump ensures a constant movement of water through its interior chamber.

The positive features of the heating equipment, dry type are:

• high efficiency level - 70-80%;
• minimum water hammer at startup;
• possibility of horizontal and vertical location of the engine;
• pumping large volumes of coolant due to high power.

Due to the combination of efficiency and noise "dry" pumps are used mainly in industrial heating systems, office buildings and large residential buildings.

Therefore, this kind of devices are the following negative aspects:

1. High noise level that does not allow to use them in the apartments.
2. The need to replace the sealing discs every 2-3 years.
3. High probability of leakage of coolant to the outside at the tightness of the working chamber.
4. The need for external cooling of the engine.

Because of the heavy weight of such equipment placed on the floor or hung on brackets.

There are two variants of the structural performance of "dry" pumps:

1. monoblock. Motor and metal body unit combined into a single structure with the specific bindings.
2. Cantilevered. By housing the equipment with universal mounts can be attached drive of any capacity.

"Dry" circulating device for heating systems, with a corresponding service are more durable, so they are gradually replacing the market model glandless.

Option # 2 - Pumps with wet-type rotor

The principle of operation of the circulation device with a rotor relating to the wet type, similar to his brother in the "dry" version: during rotation of the impeller coolant supplied to the center moves to the periphery of the working chamber, from which is collected in allocating channels.

Rotor "wet" contacts the coolant pump, and which provides cooling for the engine. Such instruments must not be operated in a dry mode, because they quickly overheat and burn.

Components of the equipment typically located in a single housing and form a single structure, however in case of breakage of the individual elements is not replaced, and buy a new pump.

The advantages of the unit to "wet" the rotor species:

• quiet operation;
• compact size;
• small power consumption (30-50 W);
• duration of maintenance-free operation;
• relatively low cost;
• ease of installation.

Devices are often inserted directly into the design of domestic boilers, facilitating consumer a choice of equipment for installation of the heating system.

In heaters of this type there are also disadvantages:

• the structural limit of maximum power;
• low maintainability;
• small efficiency (40-60%);
• need for strict horizontal axis of the motor arrangement.

Due to the low power "wet" kind of pumping machines are mainly used in heating systems of apartments and single-storey houses.

Benefits circulation devices

Until 1990, heating systems in private buildings were designed and built mainly without pumps. Heat transfer fluid moving through pipes by gravity, and its circulation is ensured by convection currents of fluid when it is heated in the boiler. Currently still using the system natural circulationThough not so often.

Now the movement of the coolant is carried out forcibly by a water pump, which have a number of advantages:

1. The reduced load on the boiler by reducing the difference in temperature in the incoming and outgoing pipe.
2. Uniform distribution of heat through the rooms of the same due to the coolant temperature over the entire length of heating rings.
3. The possibility of operational control coolant temperature.
4. Rapid heating of the heating system when starting a cold boiler.
5. No need for pipelines with a gradient device to the boiler providing a spontaneous movement of the fluid.
6. The ability to use thin tubes that occupy a little interior space of the apartment.
7. Power Pump allows the heating circuit inject a pressure sufficient for supplying coolant into several floors upwards.
8. The use of valves on the individual loops of heating networks.
9. The possibility of integrating the pump in the automatic control system of the boiler.

When the mass of advantages in circulation devices, there are two drawbacks - it is dependent on supply and additional energy costs.

But the cons are easily compensated - installation of the water pump can save 10-20% of fuel and the share of energy costs in total expenditure on heating is only 3-5%. Furthermore, the frequent lack of electricity can be set ups that will provide for a certain period of autonomous operation of the boiler and pump.

Features marking equipment

Uniform labeling requirements circulators, unfortunately, no. Manufacturers themselves choose the list of technical characteristics that are indicated on the device.

The front panel is usually displayed following information:

• movement direction of the coolant;
• merging pipe diameter;
• maximum allowable pressure;
• manufacturer and model;
• maximum working temperature;
• degree of protection;
• the operating parameters of the power supply;
• signs of compliance with national technical regulations.

Manufacturers may indicate other information at your discretion. Detailed specifications of devices specified in the instruction manual.

Units of measurement are different in different countries, so the numbers refer to the body can be deceptive. It is better to once again open the manual, which, along with the characteristics indicated and their units.

What to look for when choosing a pump?

Selection of a separate pump for the heating circuit to be performed taking into account many parameters.

Technical parameters of the equipment

Circulating equipment has a number of characteristics that are particularly important to consider when buying.

These include:

1. efficiency - the ratio of consumed electric energy to useful work performed by pumping coolant.
2. pressure - the pressure difference between the outgoing and the pump inlet.
3. Water supply - the maximum amount of coolant being pumped through the process chamber with minimal resistance of the heating circuit.
4. Power electricity consumption.
5. The diameter of the pipes - the nominal value of an attached equipment.
6. The maximum pressure rating (Denoted PN) in the working circuit at 20 ° C, at which the still functioning device is guaranteed for a long period within the warranty period.

These data are usually enough to confirm the adequacy Performance parameters pump heating system.

In more detail the selection criteria we reviewed in this article.

Sufficient capacity of the device

The choice of a particular model of the circulation of equipment affect the technical characteristics, as well as the financial capacity of the buyer and the properties of the heating system. If desired, save it is important that the pump power was enough for the normal operation of the boiler. Indeed, given the level of instruction in the water supply is always much more factual.

For self-determination of the adequacy of the power unit will hold the three stages of the calculation.

Step # 1 - determine pump performance

Determination of the required pump performance formula.

For the apartments in MDU thermal heating power is taken equal to 75-80 W / sq. m for buildings -. 100-120 W / sq. m. The difference in temperature at the boiler inlet and outlet thereof is usually 10 ° C.

It turns out that 60 square meters for a flat area. m. will be sufficient in the actual pump output (80 * 60) / (1.16 * 10) = 414 (l / h).

Step # 2 - calculate the pressure value

Determination of the total pressure to overcome the hydraulic resistance of the formula system.

This formula requires complex calculations using the reference data, so for home and residential heating systems can use a simplified graph.

According to the graph, the pressure loss in the flat pipes with a diameter of 20 mm was 70 mm / m, while taking into account the pipe length 50 m. - 3.5 meters. This figure should be multiplied by a factor 1,3-2,2, taking into account the water resistance of the armature.

Step #3 - determine the power of the pump

Determination of pump power sufficiency scheduled pressure-flow characteristics.

Such a schedule is specified in the instruction manual, and it is unique for each pump model. If the point of intersection of the parameters calculated above is below the curve B, the device is suitable for the heating system, and if the above is not present.

Detailed recommendations for the calculation of the circulation pump with concrete examples we have given the following article.

Additional features of the device

If the heating system is critical to the constant movement of the liquid, it is possible to install a pair of successively arranged in the pump circuit. The second motor in such a system can be switched on at a power failure or breakdown of the first motor.

For the automation of the boiler with the heating of the heating circuit pumps can be used with a thermostat and timer. Integrated mechanism provides ON and OFF depending on the engine coolant temperature and the time of day.

The heating of branched networks can be used with circulation pumps and a thermostat stepless speed impeller. Using them in different control loops occurs independent coolant velocity, depending on its temperature. Pumps with control unit are at times more expensive and rarely used in homes and small apartment buildings.

In the market as a model with the standard, and with an unusual structure, imparting additional functionality. Ranking of the best heating pumps, compiled taking into account comments of actual users, we brought here.

Other pump selection nuances

It is important that equipment only fulfills its function, but also to work for a long time without causing inconvenience to tenants of houses or apartments.

Therefore, when choosing the device should adhere to the following rules:

1. Choose well-known manufacturers of pumps: Calpeda, Grundfos, WILO. The price of their equipment more than 20-40%, but the probability of failure is much less.
2. Taking the characteristics of the device, which is 20-30% higher than calculated. This stock will reduce the operational workload and increase the lifetime of the equipment.
3. Pay attention to the size of the pump was placed in the place reserved for him.
4. Instrument operation should be as quiet as not to disturb residents at night.
5. No need to strive to buy a model with a capacity that greatly exceeds the calculated parameters. This will only lead to the overuse of electricity, but also to excess noise.
6. Choose exactly pump for heating systems, because they are designed to work the temperature to 130-150 ° C.
7. It is desirable that the device has a built-in grid for filtering solid particles suspended in the coolant.

The performance of the equipment must always correspond to the parameters of the heating system, this can not be saved. In addition, expect to pay as little as a reliable manufacturer, increased security and housing system of automatic operation of the regulation.

Most domestic circulation for heating devices require no configuration. For their start-up enough to connect the pipes to the pipe and turn the unit into the power grid. And how to perform the installation of the pump we reviewed step by step instructions.

Conclusions and useful videos on the topic

How to choose a good circulation pump for heating:

Circulation Equipment DAB:

Comparison of two instruments Grundfos: UPS model and Alpha2:

Selection of the circulation pump is better align with experts. If the capacity of the equipment for the standard apartments are supporting and sellers in the store before buy heater for a country house will have to apply for complex calculations to professionals.

Keep in mind that exchange it at the store after the start of operation can not, so it is better to buy the right model.

Do you want to supplement our article useful recommendations for choosing the pump for heating? Or you notice a discrepancy between the data set? Write your comments in the comments section - your feedback, we'll take into consideration.

Or maybe you still have questions after reading the article? Ask them to our experts, ask for advice - we will try to help you.