Contents
The nominal pressure in the system ensures the normal circulation of the coolant and the pressure in the taps. But what if the pressure drops in a double-circuit boiler? Why is this happening? Main reasons:
- wrong installation,
- boiler power mismatch with your pipeline,
- flow,
- radiator damage,
- interruptions in gas supply.
Consider how to raise the pressure and what to do when the boiler does not hold it.
Varieties of pressure
Why does the pressure drop in the wall-mounted appliance? First, let’s figure out what types are and how they affect the operation of technology.
- Static. The higher the height, the higher the performance. With each meter there is an increase of 0,1 bar.
- Dynamic. Forced operation of the pump creates a nominal pressure in a closed system.
- Working. Includes the above two options.
- Excess. It is determined by a pressure gauge as the difference between atmospheric and fixed.
- Nominal. The one indicated by the manufacturer in the documentation for a particular model.
- Max. The maximum that is allowed to avoid breakdowns and accidents.
- Crimping. Used in production for testing equipment.
In the heating circuit, the indicators are measured by atmospheres. They may vary; it is important that the value does not exceed the allowable maximum and minimum thresholds. A low value is possible only when the coolant is pumped into the circuit. In other cases, it should not deviate from the norm.
Pressure control in a gas boiler
All modern heating equipment is equipped with control sensors. The pressure sensor monitors normal operation. In case of deviation from the norm, it sends a signal to the control module, which causes the boiler to block. Additionally, an error code may appear on the display.
What pressure should be? A pressure gauge helps keep track of the values. Mounted unit “Bosch“,”Ariston“,”Navien» exit, installed in the house, supports values from 1,5 to 2 atm. A drop in performance is observed only in systems with forced fluid movement (pump).
How the equipment works
Under normal conditions, the work goes like this:
- Sensors record the temperature of the coolant. If an outdoor thermostat is installed, the burner automatically ignites and heats up.
- As the temperature rises, the pressure rises. When heated, water expands, so an expansion tank is provided to discharge excess coolant. The safety valve also discharges excess into the sewer.
- If a malfunction occurs, too much water is drained. As a result, the pressure drops.
- As soon as the temperature reaches the set temperature, the boiler switches off.
More about the operation of the expansion tank:
- The tank consists of two parts, which are divided by a diaphragm. Nitrogen is in one cavity, excess fluid accumulates in the other.
- The coolant fills it as much as the difference in the values uXNUMXbuXNUMXbof the system and nitrogen.
- As soon as heating stops, nitrogen pushes water out of the cavity by deforming the membrane.
Why did the water pressure drop
What affects the performance in the circuit:
- The installation height of the housing, as a result – the height and length of the pipes.
- The impact of liquid on pipes and other elements.
- Construction of highways.
If autonomous heating is installed in your house, then the norms depend on:
- Boiler models, piping paths.
- Places of assembly.
- The number of floors in the building.
- Characteristics of the outer pipe.
Next, we will look at reasons not related to installation. If the device releases and does not build up pressure, this may be an internal failure or external factors.
System leak
You add coolant to the circuit, but the pressure is still low. If the batteries are well heated, the moisture evaporates quickly, so the leak is difficult to detect. Take a dry napkin and go through all the pipe joints, connections. Look, perhaps puddles accumulate under the radiators.
If the leak could not be found, use a compressor.
- Disconnect the radiators from the heating device.
- Drain all liquid.
- Connect the compressor to the taps.
- Purge the circuit with air.
- You will hear an extraneous sound in those places where there is damage.
- For sealing, use sanitary tow or sealant.
Are your radiators built into the wall? Then contact the experts. They will check with a thermal imager. You will have to open the damaged area and carry out repairs.
Incorrectly selected boiler – power does not correspond to the established parameters of the pipeline. Therefore, the pressure constantly drops and does not hold.
If the values are dropping rapidly, the reason may be expansion tank. At the same time, you fill in the coolant every week, but it becomes less and less, although no leaks were found. There is also a pressure drop in the mixers.
How to gain and improve indicators:
- Shut off the water supply valves.
- Drain the circuit completely.
- Open the fitting on the expansion tank (RB) and record the numbers.
- Pump in air until all the water comes out.
- Bleed the air and repeat the steps. Make sure that the pointer on the pressure gauge does not exceed 1,3 bar.
- Open the faucets and fill with liquid.
If after the procedure the pressure drops and does not rise, inspect the membrane for damage. Replace if necessary.
Heat exchanger failure. After checking the pipes and connections, no violations were found? Inspect the radiator for damage. A large accumulation of scale on the tubes leads to frequent flushing with reagents. From this, the material wears out quickly, cracks appear.
The bithermic assembly cannot be repaired due to its design. Replacement required. If a tubular radiator is installed, remove it. Fistulas can be detected by green spots on the surface. Dry the device, clean the damaged area with sandpaper. After soldering with a soldering iron or torch.
Unfortunately, after repair, the unit will not last long. So sooner or later you will have to change it.
Problems with the make-up tap. When leaking, the faucet leads to a constant drop in pressure. How to add coolant to the system? Only a replacement part will help.
Malfunctions of the three-way valve. In double-circuit devices, the valve is used to switch flows from heating to hot water supply. Clean the valve, scale and debris may interfere with its operation.
Airiness. It is not difficult to determine that an air pocket has appeared in the batteries. This is clear from the gurgling sounds where water collides with air. Do this:
- Record the pressure gauge.
- Turn off technology.
- Place a container under Mayevsky’s faucet and open its valve.
- You will hear air flowing, liquid may drip. Wait for the hiss to stop.
- Turn on the water and supply it until the pressure gauge needle reaches the initial position. Shut off the taps.
- Start the boiler and listen to the work. If sounds are heard again, repeat the procedure.
Problems with gas in the highway
Interruptions in the fuel supply lead to violations of heating and blocking of the boiler. What are the reasons for interruptions:
- Clogged gas fittings: filters, nozzles, hose.
- Faulty or blocked gas supply valve.
- Fuel leak. Close the valves and call the gas service.
As you can see, problems with the operation of the boiler arise both for internal and external reasons. If you are unable to locate the problem, call the wizard. He will diagnose the system and fix the problem.