The law of hydraulics: any leaking fluid chooses the path of least resistance. In the heating network of a private house, the rule is as follows: the coolant pushed by the pump tends to pass through the first radiator or the shortest circuit of the warm floors. As a result, the remote rooms of the building warm up significantly worse. For even distribution of flows, hydraulic balancing of the heating system is necessary. We’ll tell you how to adjust the batteries and do-it-yourself floor heating loops.
When to balance the system
Theoretically, adjustment of heating radiators is necessary in any case. The design engineer, developing and calculating the water system, lays the coolant flow rate for each battery and floor heating circuit. After mounting, filling and crimping the pipeline network, the contractor is required to adjust the heat supply, focusing on the design parameters in the project.
An important point. The calculation of the heat demand and the corresponding consumption of heated water is done for the most adverse conditions - the minimum street temperature. Therefore, at the beginning of the settings, all the radiator and other control valves fully open, and the boiler is brought to the maximum operating mode.
Since the average homeowner only cares about the warmth and comfort inside the home, it is recommended to undertake the balancing yourself in such cases:
- The batteries near the boiler heat up noticeably more than the distant radiators, respectively, in the rooms it is hot or cool (too large a temperature difference).
- One of the radiators makes a distinct noise - the murmur of flowing water.
- The pipes monolithic in the screed warm the floors unevenly.
- In the process of setting up a new heating wiring, assembled by yourself.
Note. It is understood that the fittings, equipment and heating devices are selected correctly, the system is filled with coolant, air locks and other defects are absent. Otherwise, it makes no sense to engage in hydraulic balancing - get a zero result.
When it is not necessary to regulate distribution of the heat carrier to batteries:
- If the radiator network and underfloor heating work flawlessly. Once again, turning the valves is not worth it - you can make worse by inexperience.
- When identifying various malfunctions - air in the batteries, leakage, clogging of radiator or balancing valves, rupture of the expansion tank membrane and the like. First troubleshoot and check that the heating is working. You may not need adjustment.
- It is strongly not recommended to interfere with the central heating of an apartment building, to insert additional taps and valves into common risers. An exception is multi-storey new buildings with individual heat inputs to each apartment.
It is also not recommended to “press” the duct through the battery using a conventional ball valve. The normal position of the stem is fully open or closed; in the intermediate position, the valve will not last long.
Tools and instruments for balancing
To independently adjust the heating radiators and underfloor heating of a private house, you will need a minimum of devices:
- electronic contact thermometer;
- screwdriver;
- a lamb or a key for rotating the balancing valve stem (usually a hexagon is used);
- sheet of paper, pencil.
Reference. Professional plumbers often use a thermal imager, which gives a clear picture of the heating of all heating devices. The device is expensive, so let's get by with simpler means.
Instead of the indicated thermometer, the use of a remote (non-contact) pyrometer is allowed. Please note: the instrument measures the temperature of shiny surfaces with a slight error. The note concerns radiators with a new paintwork.
If you do not have a wiring diagram for a residential building, before starting work, it is worth sketching it on paper. The sketch will help to understand the sequence of connecting batteries to highways and remoteness from the furnace room. Also, flush the sump at the entrance to the boiler and warm up the system to a temperature of 70-80 ° C, regardless of street weather.
A great help in tuning is the modern Grundfos Alpha 3 circulation pump, which accurately shows the depth of adjustments through the mobile application. Minus - a decent price of the unit (starts from 240 cu).
Radiator network adjustment
The balancing method practiced by our expert is equally suitable for closed single-pipe and two-pipe heating systems of country cottages. Collector wiring and underfloor heating are regulated in another way, which we will discuss in the next section.
The essence of the technique is to measure the surface temperature of all radiators and eliminate the difference by limiting the flow of coolant balancing valves. How to adjust the heating batteries using a thermometer:
- Warm up the heat carrier to 70–80 ° С, fully open all control valves. If the boiler does not show the actual temperature of the supply water, determine it yourself by attaching the meter to the metal outlet.
- Measure the surface temperature of the first one at the radiator feed in two places - near the supply and return connections. If the difference lies within 10 degrees, the battery warms up normally.
- Repeat the operation on all radiators, recording the readings. Move along each branch of heating, alternately registering the temperature of the batteries until the last.
- If the temperature difference in the supply of the first and last radiator does not exceed 2 ° C, close the valves of the first two batteries by 0.5-1 revolution and repeat the measurements.
- When the difference reaches 3–7 degrees, the control valves of the first heaters are closed by 50–70% (count by the valve speed), medium ones by 30–40%, and the last devices remain fully open.
- Wait 20-30 minutes, allowing the batteries to warm up after the new settings, then repeat the measurement. The task is to achieve a normal difference of 2 ° C (for extended highways 3 degrees are allowed) between the last and first device.
- Repeat the setup procedure, spinning the balance valves a quarter or half a turn, until you achieve the same warm-up of all the batteries. “Listen” to each radiator for noise, indicating increased flow rate.
An important point. Do not get carried away by over-tightening the taps; you won’t get any savings in this way. Compare the temperature at the inlet and outlet of the heater - if the difference exceeds 10 ° C, the valve must be released. Due to the too low flow rate, the room will become cold.
The approximate battery adjustment of a closed two-pipe system is shown by the example of a heating scheme for a two-story house. Why approximate: the number of lockable batteries and the number of turns of the crane is strictly individual for each wiring, it is necessary to understand the place. If you doubt the correctness of your actions, press down the coolant gradually, making half a turn of the valve and repeating the measurements.
Underfloor heating and beam wiring
Since the underfloor heating circuits and the radiators of the radiation circuit are connected to a common comb, balancing is done directly on the collector. The setting method depends on the availability of flowmeters - transparent flasks of flowmeters installed on the supply or return line.
In order to correctly adjust the flow of the coolant by rotameters, it is necessary to calculate the water flow for each loop according to the formula:
- G is the mass flow rate of heated water flowing along the circuit, kg / h;
- Q - the amount of heat that the circuit or radiator should emit into the room, W;
- Δt is the temperature difference at the inlet and outlet of the loop, the calculated value of 10 ° C is taken.
The power of one floor circuit Q is determined based on the heat demand of a separate room. The parameter is considered by the specific ratio of 100 W / m² of room area or by the method of calculating the heating load. Scales of flowmeters are marked in l / min, which means that the result must be divided by 60.
Calculation example. To heat a room with an area of 10 squares, 1 kW of heat is required. The coolant consumption will be 0.86 x 1000/10 = 86 kg / h or 86/60 ≈ 1.43 l / min.
Clarification. If a large room is divided into 2 identical heating monoliths with separate water loops, the calculated flow rate is also divided in half.
Further balancing of the underfloor heating loops is done according to the instructions:
- In a filled and pressurized system, turn on the underfloor circulation pump. It is not necessary to start the boiler.
- Use the manual adjustment caps to close all thermostatic valves on the second part of the comb.
- Open the first valve fully and adjust the corresponding flowmeter. The desired volume of the duct is set by rotating the lower ring of the flowmeter.
- After setting, close the valve again and proceed to the next circuit. At the end, open all the regulators and once again check the flow rate of the water flowmeters.
Reference. On collectors of different manufacturers, flow meters are installed on the feed or reverse comb (structurally they also differ). To adjust the maximum flow, the location of the rotameters does not play a role.
Radiation batteries are balanced in the same way. For fidelity, you can combine 2 options - according to the estimated flow rate and the surface temperature of the radiator (the method is described in the previous section).
If, in order to save money, you managed to buy a collector without rotameters, the setting will stretch for several days. The task is to achieve the same temperature in the return pipelines of all the loops. That is, the initial installation is done approximately according to the power and length of the circuit, then the return temperature is measured and the flow value is adjusted.
To check the balancing of the underfloor heating, the boiler must be started. Negative point: after adjusting the flow rate, you will have to wait several hours until the concrete thickness warms up, and the temperature of the return hoses stabilizes.
Conclusion
A radiator heating network with small branches is balanced without any problems. If the shoulder length of the two-pipe wiring varies greatly, the task is somewhat more complicated. But do not worry - a difference of 3 degrees between the last and first radiator in this case is considered the norm. Consider one nuance: the heating is balanced at the maximum heating of the system, in operating mode, the water temperature drops to 50 ... 60 ° C, the difference 3 ° C also decreases.