How to repressurise a boiler
How to reduce the pressure in the gas boiler
To understand that there is too much pressure in the system, you can use the manometers. The normal reading is 1 to 2.5 bars. If the pressure gauge needle reaches 3 bars. give the alarm. If the increase is constant, it is necessary to find the cause urgently and reduce the pressure.
Also pay attention to the safety valve: it will constantly drain water to relieve pressure
The case of the expansion tank
This tank can be located separately from the boiler or be part of the construction. Its function is to draw in excess water during heating. The hot fluid expands and becomes 4% more. This excess is sent to the expansion tank.
How to repressurise your boiler
The size of the reservoir is affected by the boiler capacity. For gas equipment its volume is 10% of the total amount of coolant. For solid fuel 20%.
Diaphragm rupture. If the part is damaged, the coolant is not restrained in any way, so it completely fills the compensation tank. Then the pressure starts to drop. If you decide to open the tap to add more water to the system, the pressure will rise above normal. Leaks will appear at the connections.
Need to replace tank or diaphragm to relieve pressure.
Pressure is lower or higher than normal. To reach normal values (nominal) in the gas boiler will help the machine pump.
- Drain all the water from the system.
- Close the valves.
- Pump the circuit until you are sure there is no water.
- How to bleed air? Through the nipple on the other side of the supply.
- Pump again until the values reach the rate specified in the manual “Ariston”, “Beretta”, “Navien” and other brands.
The location of the tank after the pump provokes hydraulic shocks. It’s about how the pump works. When it starts, the pressure rises sharply and then falls. To avoid similar problems, in a closed heating system install the reservoir on the return pipe. The pump before the boiler is plugged in next.
Why the pressure rises in closed systems
Trapped air in the double boiler. Why it happens:
- Incorrect filling with water. Air intake from above, too fast.
- Excess air must not be vented after repair work.
- Maevsky cocks for bleeding air are broken.
Worn out impeller of the pump. Adjust or replace the part.
To relieve or reduce pressure, fill correctly. The intake is carried out from below, slowly, with Maevsky cocks open to bleed excess air.
It is important to properly fill the water and bleed air. If after this the pressure is not normalized, it is necessary to drain the system
The unit serves for hot water heating. It is constructed of two insulated tubes. Cold water runs down one side and heated water flows up the other. If wall damage or leakage occurs, liquids will mingle and flow into the heating system. Then the flow rate increases.
If you do not want to repair and solder the heat exchanger, you can replace it. To do this, buy a repair kit and get to work:
The assembly is secured by two screws. Unscrew them.
There are other reasons for such problems:
- Fittings are blocked. At the intake the head rises, protective sensors block the technique. Inspect the taps and valves, unscrew them as far as they will go. Check that the valves are working properly.
- Clogged filter strainer. It is clogged with debris, rust, dirt. Remove and clean the part. If you don’t want to clean it regularly, install a magnetic filter or a backwash.
- Make-up valve is out of order. It is possible that its gaskets have worn out, then you can do with replacement. Otherwise you will have to change the tap.
- Trouble with the automatics. Thermostat or controller malfunction. The reason is wear and tear, defective factory workmanship, wrong connection. Diagnostics, repair.
Check if the boiler protection parts are working properly: pressure gauge, valve, air diverter. Clean radiators and other components from dust, soot, scale. Prophylaxis helps to prevent serious damages of gas equipment.
Pressure in the boiler is slowly dropping, you have periodically to add water to the boiler.
First, consider the cases when the pressure is constantly dropping. It’s a fairly common problem. the pressure in the heating system slowly, sometimes over several days / weeks decreases.
There are two reasons why it can happen:
The first is related to the leakage of the coolant from the system, consider how dangerous it is and how to look for leaks. The second will be related to the expansion tank, but there a whole bunch, not only a decrease in pressure
Faults in the expansion tank
Characteristics of pressure in it and in the whole system are similar and depend on the boiler modification. Standard data: 1.5 and 2 bar. Even 1-1,2 bar is enough for models with moderate capacity.
Insulated tanks have two compartments inside. with air and with heat carrier. They are separated by a special membrane. And when the coolant increases in volume it bends and thus reduces the characteristics of the second compartment.
But it must be installed in the right position first. Also, when the system is started, the pressure is adjusted and the air fills the tank through the upper nipple.
Evenly it wears down and lets air through as the coolant increases. Because of this there is a pressure drop in the tank and the boiler.
Need to replace the nipple. But it is impossible to replace this part separately, so you have to change the whole tank. Only before this operation it is necessary to make sure that the rest of the system is tight.
How to depressurize?
Occasionally it may be necessary to depressurize. To do this, you will need to turn off the pump and open the pressure relief valve. Usually it is on the pump side of the boiler if the boiler is wall mounted. It is also lowered in the boiler expansion tank. All this can be done according to the manual or ask a specialist for advice.
The reddish element to the left of the pump is a safety valve, through which the pressure is relieved
The whole process of depressurizing the boiler is performed in several steps:
- The water from the whole pipe is connected. This is the 1st step;
- The tap is shut off. All taps are carefully shut off to prevent leakage;
- The pipeline is pumped by the pump. This is to make sure that the coolant is fully drained;
- The heating medium is started up with an open air vent.
Do the same thing until the reading is good.
Rapid temperature fluctuations can lead to defects. In order to control the pressure increase in the boiler, it is essential to occasionally create the filters cleaning. Also, the radiator and nodes that need to be cleaned from impurities and limescale.
It is important to constantly monitor the temperature and only add water when the system is cold. Preventive maintenance prolongs the operation of the boiler and reduces the risk of problems or malfunctions during the heating season.
The adjustment of the actual values is based on the properties of the device, the temperature of the thermal fluid, the volume of the circuit. All the necessary characteristics for the trouble-free operation of the boiler are thoroughly described in the annotation.
An increased temperature in the heating medium inevitably results in an increase in pressure in the circuit, a decreased temperature results in a decreased pressure in the circuit. For this reason, you should measure the pressure only before and after the heating.
The small permissible value is approx. 0.9 bar. Readings below 0.5 bar can cause a tragedy and stop or inevitable damage to the device. The pressure in the system should not be higher than the permissible norm for the components.
A few basic rules must be observed to ensure that the system operates without interruptions. It is important to correctly install and connect the boiler. Check the system before start-up and treat the coolant.
The control of the pressure characteristics in the boiler helps to identify faults or damage and remove them at an early stage. Personal meters can be of great help in this matter. In the case of a sharp drop in pressure identify the cause and promptly remove it. Then the heating boiler will serve for a long time with constant care.
In this video we will give you instructions on how to use the Vaillant gas boiler:
The work of all parts of the boiler is constantly monitored by a system of sensors. If an abnormality occurs, they give a signal to the control board, which is shown on the display.
Problems with pressure in Vaillant dual circuit gas boiler. What to do?
|F.00||Supply thermistor circuit breakage|
|F.01||Circuit breakage of mower return thermistor|
|F.02-03||Open circuit of thermistor of temperature or storage sensor|
|F.04||Return thermistor breakage|
|F.10||Supply resistor short circuit (exceeds 130°)|
|F.11, F.14||Return thermistor short circuit (exceeds 130°)|
|F.22||Dry run (pump malfunction)|
|F.23||Water shortage. Determined by temperature difference between forward and return line|
|F.29||Failure in operating mode (occurs with flame extinction and failed ignition attempt)|
|F.35||F Fault in the gas outlet|
|F.37||Unstable or abnormal fan speed|
|F.72||Wrong readings on the forward and/or backward mowing line sensors|
|F.75||Pump can not rise the pressure|
|F.76||Primary heat exchanger overheating|
This or that error does not always mean breakage. You need to restart the boiler and see if the error appears again, or not.
How to increase the pressure in the heating system of the wall boiler Vaillant-Vaillant.
If after several attempts the error appears again, contact a service organization.
The most common malfunctions and their causes
Despite the true German quality, as well as any other equipment, the Vaillant boilers are subject to various kinds of failures. If a problem does occur, the unit informs the owner by displaying an alphanumeric code on the LCD screen, including a red light, as mentioned above. Each error has its own code.
If you study thematic forums, where owners of boilers discuss their malfunctions, the most popular requests are these:
- Error code F22, which indicates lack of water in the device or shortage of water. It is worth checking whether the pump is not jammed, whether the pump cables are securely connected to the water pressure sensor, look at the sensor itself or the pump power. There may also be poor water circulation;
- error code F28, in which the unit does not start at all. There could be different reasons: wrongly connected phase and zero, oversaturation of gas with air, too low gas pressure, broken control board, wrong grounding of boiler, ruptured cable or faulty connection to gas mains. Some problems can be solved by the user manual. For example, check if the gas tap is open or change the gas pressure in the boiler settings to 5 mbar;
- Error code F29, when the burner flame goes out constantly and new attempts to ignite the burner are unsuccessful. Causes may be: the gas boiler is not properly grounded, gas supply malfunctions in the gas system itself, problems with the ignition transformer or with the gas valve. To eliminate this problem it is worth checking the gas pressure, it may be too low, or see if there is enough air for normal combustion of the fuel;
- Error code F36 (Vaillant Atmo), when the combustion products are escaping. This problem could be caused by poor ventilation in the room or poor draft in the chimney, or the temperature in the room is too high. You should also check whether sufficient clearance is made between the boiler and the wall;
- Error code F75, when the boiler pump works but the pressure is not increased. There can be several reasons too: breakage of the pump or water pressure sensor, air in the heating system, incorrect connection of the expansion tank or insufficient water pressure. To fix the problem, you can try to clean the water pressure sensor or you will have to buy more powerful components.
Boilers Vaillant series AtmoTec have many sensors and mechanisms, which make their operation as safe as possible. Let’s see them in detail.
If the batteries in the room are unevenly heated, increase the rate of circulation of the coolant. To do this turn the bypass screw clockwise.
If when you turn on the heating in the radiators, on the contrary, the liquid noises, then reduce the speed of the coolant by turning the screw in the opposite direction. Use a manometer or digital pressure gauge to set and measure. It will indicate the nominal pressure, which should not exceed 0.2-0.4 bar.
Why does the pressure in the wall-mounted appliance drop?? Let’s start by examining what types there are and how they affect the operation of equipment.
- Static. The higher the height, the higher the reading. Each meter goes up by 0.1 bar.
- Dynamic. Forced operation of the pump creates a nominal head in a closed system.
- Working. Includes the above two variants.
- Excess. Determined by the manometer as the difference between atmospheric and fixed.
- Nominal. That specified by the manufacturer in the documentation for the specific model.
- Maximum. The maximum allowed to avoid damage and accidents.
- Pressurize. To be used in production when checking the equipment.
In the heating circuit the values are measured in atmospheres. They can vary; it is important that the value does not exceed the allowable maximum and minimum thresholds. Low value is possible only when the coolant is pumped into the circuit. In other cases it should not deviate from the norm.
Why pressure rises in closed systems
Air accumulates in the two-circuit boiler. Why it happens:
- Filled with water incorrectly. The intake is carried out from above, too fast.
- Excess air not vented after repair work.
- Broken Mayevsky cocks for bleeding.
To relieve or reduce pressure, fill the fluid correctly. The intake is carried out from below, slowly, with the Maevsky cocks open to bleed excess air.
Problems of an open system
The problems are the same as described above. It is important to properly fill the water and bleed the air. If afterwards the pressure has not returned to normal, the system must be drained.
The node is used to heat DHW. Its construction consists of two insulated tubes. Cold water flows through one, the other already heated. If the walls are damaged, a fistula appears liquids mix and get into the heating part. Then there is an increase in pressure.
If you do not want to repair and solder the heat exchanger, you can replace it. To do this, buy the repair kit and get to work:
The first start of the boiler and the adaptation period
For the possibility of warranty service of your unit, the first start-up should be carried out by a service organization. Boiler can be started only after finishing construction and repair works, in the room where the boiler is located.
Trial run of a two-circuit boiler consists of the following activities:
- The fulfillment of the installation requirements;
- Check the tightness of all nodes and connections;
- Starting the unit, setting the parameters;
- Putting on warranty service.
Initially, with the help of a make-up faucet, which is usually located at the bottom of the device, the system is slowly filled with water. Watch the pressure gauge readings. The pressure must be within the limits specified in the manual of the particular appliance. As soon as the pressure gauge shows a sufficient value, the make-up valve must be closed.
then ensure that there is no residual air in the radiator and circulation pump. Most modern models are equipped with a device for venting, but they do not always give the desired result.
Using the Mayevsky tap to bleed air from the radiators, the tap is open until water flows from the battery. After draining the air from all the radiators, the pressure in the system drops, so you need to re-supply it with water to the right pressure.
After that air is removed from the circulation pump. After opening the lid of the boiler, turn on the unit. At the same time, you will hear the pump turn on, making a rumbling, gurgling sound. These sounds indicate that the boiler is leaking. Using a screwdriver, slowly unscrew the bolt that is in the center. After water appears from under it, the bolt is tightened.
It should be done this way several times until all the air has been bled out. You will be able to tell by the even sound. Further should work the ignition and start the boiler. Watch the pressure gauge and if the pressure drops, add water.
While the system is warming up, unscrew the farthest radiators to full, the closest ones, on the contrary, with the taps that are located on the radiators. The adaptation period usually lasts for a few days, when you need to regularly bleed and add liquid to the system.