Why Does The Pressure Drop Or Increase In The Heating System Circuit Reasons?

2023 Author: Philip Bishop | [email protected]. Last modified: 2023-08-25 07:54

• System pressure drops
• Determination of coolant leaks
• Pressure drops associated with boiler faults
• System pressure exceeds the recommended threshold

Modern gas boilers and the pragmatic striving of the thermal power industry for progressive solutions to heating issues in private households, apartments are increasingly leading to the use of closed heating systems with forced circulation of the coolant. The closed circuit of the liquid circulation allows to increase the operating pressure of the system and thereby increase its safety, because it is known that with an increase in pressure in a liquid medium, the temperature of its boiling rises. In particular, the following ratios are characteristic of water: 1 atm. - 100 degrees, and 2 atm. - 120 degrees.

The state of the liquid filling of the system is monitored by measuring instruments. First of all, gas boilers equipped with a circulation pump and a safety group require a mechanical dial or electronic display reflecting the readings of temperature and pressure sensors located at the boiler outlet (supply). Additional pressure gauges are installed on distribution manifolds, which are responsible for supplying the coolant to various parts (floors) of the building. Systems that include boilers for indirect or combined heating of water, as well as complex systems using a high-temperature circuit - radiator heating and a low-temperature circuit - warm floors, cannot do without indications of auxiliary pressure gauges.

System pressure drops

We will name the reasons that answer the question of why the pressure in the heating system drops, and suggest ways to eliminate them. So, the reason for the negative phenomenon is:

• unauthorized leakage of the coolant at the joints of the pipes with heating devices or directly a burst of main pipelines, violation of the tightness of pipes in warm floors;
• breakdown of the heating unit itself, caused by the formation of microcracks in the heat exchanger body;
• breakdown of a membrane-type explosive valve, which is part of the boiler equipment safety group;
• rupture of the membrane in the expansion tank, designed to compensate for the linear expansion of the coolant with an increase in its temperature;
• depressurization of the hot water supply (DHW) circuit in the bithermal version of a generating heat installation, hence the pressure in the double-circuit boiler drops during the intensive analysis of hot water and increases sharply when it stops.

Determination of coolant leaks

The leak is initially determined visually, for this, as a rule, the system is fed to the recommended level and the forced circulation of the liquid is stopped. Particular attention is paid to the shut-off and control valves installed on heating radiators, their direct connection to the main pipes. If it is not possible to independently determine what caused the pressure loss in the heating system, then they resort to the services of specialists. With the help of pressurization with air, a more intense release of the coolant is achieved at the leak points. Sometimes, elimination simply requires repacking the connection or replacing a defective fitting. A more sophisticated device requires the determination of a burst in pipes hidden in the wall or in the "snails" of a heated water floor. For this, special scanners are used,determining with high accuracy the concentration of excess moisture. Then it's a matter of technology: dismantling the decor of the wall or floor surfaces, excavating the damaged area and replacing it. Ways to eliminate leaks in heating.

Pressure drops associated with boiler faults

If it is found that the pressure in the gas boiler is dropping, then only employees of the service organization are involved in troubleshooting, on the balance of which the heating unit is located, as a device of increased danger. The qualified personnel of the service center will offer several solutions to the problem: perform soldering or replace the entire heat exchanger. Everything will depend on the nature of the damage resulting from regular flushing of the boiler thermal "jacket" from scale, factory hidden defect or banal operational wear. After the specialists carry out the work, the corresponding records are made about the warranty or post-warranty repair. Having determined that the pressure in the double-circuit boiler is falling due to damage to the rubber membrane of the expansion tank,it is necessary to replace the damaged product with a new tank in order not to expose the entire heating system to additional risks that will arise after the system is fed to the set level. The liquid, having lost the opportunity for linear expansion, will lead to the fact that the pressure in the circuit will rapidly increase, causing frequent operation of the safety valve. Damage to the diaphragm (EPDM) in the safety valve triggers the protective function of the device even if the maximum pressure in the heating system has not been reached, which prescribes an emergency discharge of excess fluid from the circuit.that the pressure in the circuit will rise rapidly, causing the safety valve to operate frequently. Damage to the diaphragm (EPDM) in the safety valve triggers the protective function of the device even if the maximum pressure in the heating system has not been reached, which prescribes an emergency discharge of excess fluid from the circuit.that the pressure in the circuit will rise rapidly, causing the safety valve to operate frequently. Damage to the diaphragm (EPDM) in the safety valve triggers the protective function of the device even if the maximum pressure in the heating system has not been reached, which prescribes an emergency discharge of excess fluid from the circuit.

System pressure exceeds the recommended threshold

The fact that the pressure in the heating system rises indicates the presence of one of the reasons on this list. So:

• a drop is observed in a certain section of the circuit - circulation is stopped after the regulating devices;
• continuous feeding of the system is carried out;
• shut-off valves cut off entire circuits or sections of trunk pipelines;
• an obstacle that makes it impossible for the circulation of the coolant in the system due to the critical accumulation of air masses;
• mechanical clogging of systems and devices for liquid filtration installed in the heating circuit.

Troubleshooting involves a sequential examination of the entire space heating circuit. As a result of oversights, unauthorized intervention of curious children, it is possible that valves, gate valves, ball valves are closed. Disconnection of control devices from the electrical network (servo motors for collectors or thermostatic three-position valves when connecting DHW circuits in a combined boiler) can also affect. They resort to preventive washing of mechanical filter meshes. Particular attention is paid to self-flushing filters, which are mandatory installed on old heating systems where cast-iron heating devices and metal pipes of large cross-section are used. Pressurize the heating system, and, if necessary, replace the device for automatic venting,repair the valve responsible for feeding the heating circuit in the boiler.

Thus, by constantly maintaining the operating pressure in the heating system of 1.5-2 atm., We get the opportunity to efficiently and safely use the boiler equipment, we achieve the optimal physical load on the devices and heating pipelines, thereby increasing the terms of their trouble-free operation.