The working volume of the coolant in the heating network may decrease due to a number of reasons - leakage, evaporation, steam discharge through the automatic valve, and repair work. In the open type scheme, the main riser is emptied and filled with air from the expansion tank, closed - the pressure is significantly reduced. In any case, it is necessary to replenish the heating system, which can be done in several ways.
Signs of critical heat transfer shortage
Not all owners of private homes monitor the technical condition of water heating, it works - okay. When a latent leak is formed, the system continues to function for a while, until the amount of coolant drops to a critical level. This moment is monitored by the following criteria:
- In an open system, the expansion tank is first emptied, then the main riser, which rises from the boiler, is filled with air. Result: cold batteries during overheating of the supply pipe, switching on the maximum speed of the circulation pump does not help.
- The lack of water during gravity manifests itself in a similar way, in addition, you can hear the gurgling water in the riser.
- On the gas heater (open circuit), frequent starts / starts of the burner are observed - clocking, the TT-boiler overheats and boils.
- The lack of coolant in a closed (pressure) circuit is reflected on the pressure gauge - the pressure gradually decreases. Wall-mounted models of gas boilers automatically stop when falling below the threshold of 0.8 Bar.
- Floor-mounted non-volatile units and solid fuel boilers continue to regularly warm the remaining water in a closed system until the volume released by the coolant is filled with air. The circulation will stop, overheating will occur, the safety valve will operate.
Important clarification. When boiling a TT boiler operating in an open gravitational system, an explosion will not follow, since the coolant communicates with the atmosphere. The water heated by the heater will evaporate, then a fire will start in the boiler room. Although the described process takes a lot of time, such situations are far from uncommon.
Why do we need to recharge the system, we will not explain - this is an obvious measure to maintain the efficiency of heating. It remains to choose a method of replenishing the heating system.
Choice of refueling option
Several methods are used to replenish the coolant supply:
- Manual recharge is the cheapest and most versatile option, suitable for all types of wiring.
- Automatic replenishment from the water supply system is practiced only in systems operating under pressure.
- A manual pressure pump is also used to refuel a closed network with a non-freezing coolant. An automated circuit device with an electric pump station connected to a tank with antifreeze is practiced in industrial boiler rooms.
Note. If the radiator network and underfloor heating are filled with antifreeze, simple make-up is done with a small hand pump. But most often, filtered tap water is used in the heating system, why - because of the price of non-freezing coolants (especially harmless propylene glycol).
The principle of operation of the automatic make-up unit is based on the operation of a pressure reducing valve that responds to a decrease in pressure in the heating system. When it falls below the set value, the valve mechanism opens and starts the water from the line. Similarly, a pumping station operates, injecting antifreeze from a separate tank.
We take the liberty of recommending the use of a manual recharge scheme. Causes:
- The node consists of 2-3 inexpensive elements and will never turn on without the knowledge of the homeowner.
- No matter how reliable and high-quality the heat network is mounted, the likelihood of leakage and actuation of the valve exists.
- Situation: pipe breakthrough, prolonged flow of coolant in the absence of hosts. A fully autonomous “smart” make-up will flood the entire house, ruin the flooring and costly repairs.
- Imagine an identical situation in an apartment building - a leak from an individual system and the inclusion of automated replenishment will flood the neighbors from below.
- The smallest sand will accumulate under the valve seat and the element will lose its tightness over time. Under pressure from the side of the 4-7 bar water supply, spontaneous make-up will begin. The most harmless scenario is the dumping of excess coolant through a fuse on the boiler safety group.
Than to eliminate the consequences of the described troubles, it is better to allocate a fraction of the time for personal control over your heating. If you find signs of loss of coolant, you will decide on your own whether to energize the system immediately, look for leaks or repair. For a negative example of using such automation, look at the video of our expert:
Manual recharge scheme
The simplest version of filling the system is implemented in 90% of double-circuit wall-mounted boilers, where a priori a cold water supply pipe is connected. A manual valve is installed inside the casing, connecting this line to the return heating line. Often, a boiler feed tap is found on solid fuel heat generators with and without a water circuit (for example, heating units of the Czech Viadrus brand).
Reference. For some models of gas heaters equipped with a hot water heat exchanger (in particular, Beretta), manufacturers instead of a manual tap install an automatic recharge valve with an electromagnetic actuator. If the coolant pressure drops below 0.8 Bar, the boiler itself draws water to the required level.
To build a classic make-up assembly suitable for any type of system, you will need the following details:
- a tee with a lateral branch Du 15-20, corresponding to the material of the heating pipe, - fitting for metal-plastic, polypropylene and so on;
- poppet (spring) check valve;
- ball valve;
- couplings, fittings.
The purpose of the check valve is to keep water from the heating network back into the water supply. If we are talking about pumping antifreeze with a pump, you can’t do without a valve at all. The fittings are installed in the order of listing:
- The tee crashes into the heating return line after the circulation pump.
- A check valve is connected to the branch pipe of the tee.
- Following is a ball valve.
Tip. If there is no fine filter at the water supply entrance to a private house, it is advisable to provide such a filter on the make-up line. The element will protect the heating system from the ingress of fine sand and rust particles accumulating on the check valve plate and in the seats of the three-way valves.
The principle of operation of the unit is simple: when the tap is opened, water from the centralized line enters the heating pipelines, since its pressure is higher (4-8 Bar versus 0.8-2 Bar). The filling process of a closed system is monitored by the pressure gauge of the boiler or safety group. If you accidentally exceed the pressure, use the Mayevsky tap on the nearest radiator and bleed off excess water.
To control the amount of coolant in the expansion tank of the open heating system located in the attic of the house, the tank must be equipped with 2 additional pipes with a diameter of ½ inch:
- The control pipeline, ending with a tap in the boiler room, cuts into the side wall at about half the height of the tank.By opening this valve, you can determine the presence of water in the tank without climbing into the attic.
- The overflow tube cuts 10 cm below the tank cap, the end is diverted to the sewer or simply to the street under the roof overhang. Being in the furnace and opening the feed valve, you should see this pipe, when water flows from there, filling stops.
Comment. If you are interested in calculating the minimum volume of expansion capacity, click on the highlighted link.
Automatic make-up unit
If you are confident in the reliability and quality of the system assembly, you can mount an automated circuit that adds water from the HVS pipe. What you need to buy:
- pressure reducing valve (easier - reducer);
- 3 ball valves;
- 2 tees;
- pipe for bypass device.
An important point. Water entering the gearbox must first be cleaned with a coarse strainer, otherwise the valve will become clogged quickly. If such a filter is not provided at the entrance to the building, install it in front of the feed unit.
The main actuating element of the circuit - the gearbox - consists of the following parts:
- fine filter at the inlet;
- spring seat valve with rubber seals;
- pressure regulator handle with a printed scale, range - 0.5 ... 4 Bar (or higher);
- manual shutoff valve;
- outlet check valve.
Note. There are more expensive models of make-up reducers with a built-in pressure gauge that measures the pressure on the side of the heating system. Since this device is already in the safety group or boiler, it makes no sense to spend extra money and duplicate it. An exception is when recharge is embedded far from a heat source (read the next section).
As you can see, the reduction machine already contains all the necessary elements - a filter, a check valve and a regulator. It remains to assemble a simple circuit with a bypass and service cranes designed to remove and maintain the gearbox.
It is simple to control the valve - use the regulator to set the minimum pressure threshold in the heating system, open the taps of the direct line, and close the bypass. How to correctly adjust the automatic valve is shown in a short video:
Tip. If you plan to put a coarse filter in front of the gearbox, provide an additional service tap in order to clean the mesh without turning off the water in the whole house.
To organize the automatic addition of antifreeze to the system, it is possible to adapt a “hydrophore” - a water station with an electric pump designed for water supply from a well. The unit pressure switch must be reconfigured for a minimum pressure of 0.8 Bar, a maximum of 1.2 ... 1.5 Bar, and direct the suction pipe into a barrel with a non-freezing coolant.
The feasibility of this approach is very doubtful:
- If the “hydrophore” works and starts pumping antifreeze, you still have to look for and eliminate the cause of the problem.
- With a long absence of hosts, recharge will also not save the situation in the event of an accident, since the size of the tank is limited. The pump station will extend the heating operation for some time, but then the boiler will turn off.
- Putting a big barrel is dangerous - you can flood the toxic house with toxic ethylene glycol. Non-toxic propylene glycol is too expensive, as is the elimination of the spill.
Conclusion. Instead of additional pumps and automatic gearboxes, it is better to purchase an Xital electronic unit. After a relatively inexpensive installation, you will be able to control the operation of heating through a cell phone or computer and quickly respond to emergency situations.
How to connect to the heating system
With a closed circuit, there is no big difference where to connect the make-up pipeline - to the supply or return.We recommend using the classic proven technique - the tie-in point should be located on the return line next to the boiler, after the circulation pump and expansion tank. Causes:
- the unit is located in the furnace room, next to equipment and devices;
- pumping water into the return line is immediately reflected in the pressure gauge installed at the supply behind the boiler;
- the insert is located at the lowest point, the flow is distributed in 2 directions - into the boiler and radiators, air is squeezed out evenly.
The binding of solid fuel assemblies involves a condensate protection circuit with a three-way valve. You can not make recharge in front of this valve - it will immediately close from cold water and the boiler pressure gauge will start to delay with the readings. Crash inside the circuit, between the 3-way valve and the heat generator.
Similarly, make-up crashes into the return pipe of an open system. The second option is to add coolant directly to the tank, the disadvantage of this method is to lay the supply pipe to the attic.
Connecting the make-up line is allowed at other points:
- to a separate fitting of a solid fuel boiler provided by the manufacturer;
- to the bottom of the water gun;
- to the return manifold of the distribution comb;
- to the output of the indirect heating boiler.
Finally, on the safe addition of coolant
When pouring water or partial replenishment, follow our recommendations:
- Replenish the preheated system slowly by opening the valve a quarter of the lever stroke. In this way, air jams can be avoided and the boiler heat exchanger will be protected from temperature shock.
- Refuel from scratch when the heat source is idle and the circulation pump is turned off.
- Check the pressure in the expansion tank and go through all the radiators, opening the Majewski taps to bleed air.
- If your boiler is equipped with modern electronics, be sure to read the paragraphs on the instructions regarding recharge. Often in the unit it is necessary to activate a special service mode.
- Excess pressure is easily vented through the nearest air vent.
Reference. Cast iron heat exchangers easily crack from sudden changes in temperature, and steel furnaces are covered with condensate from the inside. The latter is mixed with soot and forms a dense coating.
The injection of antifreeze with a hand pump does not conceal pitfalls. Crimping machines are equipped with their own pressure gauge, which allows monitoring the actual pressure at the point of insertion.