Location, principle of operation and reasons for triggering the gas boiler draught sensor

A dependable heating system is crucial for maintaining a comfortable and warm atmosphere in our homes. A gas boiler is a typical part of many heating systems, working hard in the background to provide us the heat we require. However, have you ever given any thought to the tiny but essential draught sensor device? We’ll explore the location, purpose, and causes of the gas boiler’s draught sensor activation in this post.

Let’s start by locating this small but powerful sensor in your gas boiler system. The draught sensor is usually located close to the boiler’s flue or chimney. Because of its thoughtful placement, it can keep an eye on the gases flowing through the boiler, guaranteeing safe and effective operation. The draught sensor, in spite of its modest size, is essential to sustaining peak performance.

Let us now explore the workings of the gas boiler system’s draught sensor and solve this mystery. The sensor’s primary function is to identify the existence and intensity of the draught, which is the movement of gases or air through the chimney or flue. The airflow is continuously monitored by the draught sensor when the boiler is operating. The sensor initiates a response to modify the boiler’s combustion process if it notices a change from the typical airflow pattern.

But why might the draught sensor activate in the first place? The draught sensor’s functionality can be affected by a number of things, such as variations in the weather, obstructions in the flue or chimney, or problems with the boiler itself. For example, the airflow may be disrupted by a strong gust of wind outside, in which case the sensor will adjust the boiler’s settings to account for the change.

In summary, even though the draught sensor is tiny and sometimes disregarded, its importance to a gas boiler’s efficient operation cannot be emphasized. This modest gadget makes sure that our heating systems run effectively and safely, keeping our homes toasty and cozy regardless of the outside weather by monitoring and controlling airflow.

How it looks and where it is located

A draught sensor is a mandatory feature for domestic heating boilers, as per the safety regulations for gas households (PB 12-368-00). The smoke hood, which is housed inside the smoke trap, or the empty space between the ventilation duct and the unit’s body are typically the locations of installations.

It is important to note that it cannot be firmly fixed to the gas duct’s surface. When vapor gaskets are used as a "separator," you can lessen the likelihood of contact heating and designate a gap that will allow for technical access to the draught sensor and the gas duct opening.

Device and principle of operation of the gas boiler draught sensor

Regardless of the design, the draught sensor’s basic method of operation is centered on monitoring the exhaust gas output indicators. If there is a violation, the control unit receives the necessary signal, and the solenoid valve shuts off the fuel supply to the burner, turning off the equipment.

More specifically, the following gas unit model can be used to examine the thrust sensor’s mechanism of operation and associated device:

The sensor is a thermorelle-shaped device that responds to temperature changes in an atmospheric boiler (open combustion chamber). The temperature range of the thermorelle is adjustable to 75-900 °C for natural gas and 75-1500 °C for liquefied gas. When there is less of a draught in the chimney, there is more smoke present, which raises the temperature. When the plate gets too hot, it will expand and break the contacts.

Even in cases where the root cause of the issue is promptly eliminated, you cannot resume operation of the unit until it has completely cooled down. This is because the draught sensor in most atmospheric boilers with an open combustion chamber also functions as a safety thermostat – smoke temperature controller.

The sensor in the turbo boiler (closed combustion chamber) is a pneumatic relay, whose membrane is extremely sensitive to pressure. The flow produced by the turbine or fan causes it to deflect (the manufacturer can adjust the degree of tension), locking the contacts in the closed position. Consequently, the microswitch’s contacts open when the pressure discharge level drops below the allowable limit.

Condensing boilers require specific draught sensors because their smoke temperatures are lower than those of conventional models.

Thus, the primary defense against the entry of carbon dioxide and harmful smoke into the space is the draught sensor.

How to check the function

The boiler control system records a draught sensor contact failure as a smoke extraction error, which is represented on the display by a yellow indicator light.

If the unit’s model lacks these types of information, you can look outward for clues that indicate the protective element is failing:

• the boiler periodically spontaneously shuts down, although there are no visible failures in operation (smoke emission is stable, the flame is even, there is no overheating);
• the boiler first switches on and works normally for some time, but after 20-30 minutes it switches off, and reignition is possible only manually.

One of three methods must be used to verify the operability of the sensor and confirm (disprove) that the issue actually lies there:

• attach a small mirrorat the sensor location – its surface should not mist up during active use of heating;
• half cover the flue opening – if the sensor works, the boiler switches off quickly and switches on (manually) immediately after removing the damper;
• turn off the heating circuit and fully open the DHW tap – in this mode, the boiler damping with a high probability indicates the failure of the relay.

In the event that the boiler continues to fire on occasion despite the inspection revealing three instances in which the sensor is malfunctioning, the intensity of the draught must be measured. Additionally, there is a chance that the sensor will become "idle" in the event of an automatic power supply failure, such as momentary network voltage fluctuations.

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However, there is an additional kind of malfunction wherein the draught sensor itself is working properly as a component, but false alarms arise because the contact circuit connections aren’t made correctly. The protective element must be removed and examined in order to detect this; its contacts must be free of oxidation and securely fastened to the housing.

In the event that no damage is visible, it is necessary to use a tester to measure the sensor’s resistance, which is typically very low (equal to the probes’ resistance), at most 1-2 ohms.

In the event that resistance persists, the circuit’s contacts and terminals should be cleaned with alcohol, pressed together with pliers, allowed to dry, and then replaced.

It is imperative to replace the sensor with a new one or one similar to it that has the proper temperature and pressure if it does not ring at all. к. It is beyond repair. The old sensor can be completely removed from the circuit while searching for a new one, but only if the ventilation system is functioning properly.

How to disconnect the draught sensor in the gas boiler

It makes perfect sense that someone would want to just disconnect the sensor when it actuates frequently, but this is not feasible for two reasons:

• first of all, its activation may indicate inherently poor draft characteristics of the chimney, which sooner or later will lead to the fact that the fuel will no longer have time to burn out and will begin to accumulate in the living room;
• secondly, which is even worse, it can be an indicator of a back draft, which occurs due to the formation of an "air lock", i.e., a "air lock". е. Exhaust gases reach only to a certain level, after which they return back.

Reverse draughts only occur in gas boiler models featuring an open combustion chamber because they are caused by the absence of a natural vacuum in the chimney. Because of the disruption in airflow, carbon monoxide cannot escape and instead enters the home, where it can poison the occupants.

You must realize that this is a clear violation of safety because, in the event of an emergency, the unit will not be protected, even though the design does allow you to turn off the sensor by removing the wires from the circuit connection with the solenoid valve and thermocouple breaker.

Thus, it is better to identify and remove the cause of sensor activation immediately (with the assistance of specialists) rather than taking a chance with your health.

Knowing the function of the gas boiler draught sensor is essential when it comes to heating and insulating your house. This sensor is positioned carefully inside the boiler to monitor any variations in airflow. It prevents dangerous situations like carbon monoxide buildup by sensing a drop in pressure and shutting down the boiler. The idea behind this is straightforward: combustion cannot occur safely in the absence of adequate airflow. Common causes include clogged vents or flues, which can result in inadequate ventilation and even fatal situations. Thus, the draught sensor serves as a safety measure, guaranteeing the safe and effective operation of your heating system, keeping your house warm and your family secure.

Causes of draught sensor tripping

Errors committed during the smoke exhaust system installation process are the primary causes of draught disturbance, which sets off the sensor:

• absence of a draft stabilizer, which protects against blowing wind gusts;
• incorrect installation of the chimney or inaccurate calculations of the chimney shaft dimensions;
• frequent clogging of the chimney, which indicates the need for a protective cap;
• untimely cleaning of the sensor from soot produced by burning LPG.

It is advised to periodically inspect the chimney, turbine, connection, and other related components, irrespective of the boiler’s operational quality. A master craftsman should be the only one to adjust the sensor’s clearance if necessary, as doing so will raise the operating temperature limit.

Maintaining a cozy and safe home environment depends critically on the effectiveness and safety of our gas boiler systems. The draught sensor is an essential part in this context since it controls the flow of gases inside the boiler. The sensor is positioned strategically within the system, usually close to the flue outlet. Its purpose is to monitor variations in air pressure and notify the boiler to modify its operation.

Comprehending the gas boiler draught sensor’s working principle reveals the importance of this device in protecting the occupants and the appliance. The boiler is prompted to either reduce its output or shut down when the sensor identifies a negative pressure in the flue, which can be attributed to inadequate draught. Conversely, the sensor can again activate safety mechanisms to avert dangerous scenarios like carbon monoxide leaks if the pressure rises too high, indicating possible blockages or malfunctions.

The gas boiler draught sensor can be activated by a number of factors, which emphasizes the significance of routine maintenance and attention to detail. Strong winds or variations in atmospheric pressure can have an impact on the airflow inside the flue, which may cause the sensor to activate. Furthermore, internal problems like a soot or debris buildup can obstruct the flue, resulting in erratic draught patterns that set off the sensor.

To sum up, the gas boiler draught sensor is an essential safety component that keeps our heating systems operating correctly and guards against potential dangers. Homeowners can prevent problems with their systems and maintain a secure and comfortable living space by being aware of where it is, how it works, and the different things that can cause it to activate.

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