Flame and draft sensors
Flame and draft sensors work on this principle. The draft sensor reacts to the deterioration of the smoke draft and transmits an impulse to the control system. It is located in a smoke hood. Equipped with a plate made of an alloy of two metals: iron and nickel. When the draft deteriorates, flue gases accumulate and heat up the plate. It is deformed, the contacts open at the same time, the flow of fuel into the combustion chamber stops. When the temperature decreases, the plate returns to its normal state.
The temperature sensor works on the same principle. When the water in the boiler is heated above the set temperature, the lever mechanism is activated and the temperature regulator valve closes. The flow of gas stops, the burners go out.
When the water cools, the sensor bellows compresses, the lever mechanism is activated, the temperature regulator valve opens, the gas begins to flow, and the burners light up.
The most common malfunctions of automation and methods for their elimination
Before setting up the automation on the boiler, it is necessary to diagnose it. As a rule, serious malfunctions occur that require the intervention of a specialist. Adjustment can also be entrusted to the gas master. Or you can make it yourself by reading the instruction manual.
Attention!
Before each seasonal operation, it is necessary to check the operation of the safety sensors.
Most often, the filter becomes clogged, problems arise with valves, sensors burn out due to power surges, and a gas leak is detected. Proper cleaning of the filter must be done by the master. You can try to replace electronic elements yourself by carefully studying the operating instructions for your boiler.
In order to replace the temperature sensor, it is necessary to turn off the gas boiler and cool the water to a temperature of 40 degrees. Shut off the flow of coolant, remove the control knob by unscrewing the screw. Next, remove the RTV adjustment screw. Remove sensor bellows with support washer. Loosen the union nut of the sensor bulb. Install the bulb of a working sensor into the boiler jacket and tighten it hermetically. Install the sensor bellows in the pipe seat, install the support washer on the bellows, install the PTB adjustment screw and adjust the temperature.
If there are problems with the ignition of the igniter, then one of its possible causes is a malfunction of the draft sensor. In this case, it must be dismantled, diagnosed, checked the contacts, cleaned, and, if necessary, replaced with a new one.
Also common reasons why the igniter does not ignite may be:
- malfunction of the gas valve;
- clogging of the hole in the igniter nozzle (it is possible to clean it with a wire);
- strong draft of air;
- low gas pressure at the inlet.
When turning off the gas supply, it is necessary to check the chimney (it may be clogged), the electromagnet, the gas pressure at the inlet to the gas boiler.
Attention!
For the diagnosis and repair of gas boiler automation, it is necessary to invite a specialist. Inept actions can aggravate the problem and lead to undesirable consequences. For the automation of the AGUK, AGU-T-M, AGU-P systems, the most common problem is the burnout of a bimetallic plate, which is used as a sensitive element
For automation systems AGUK, AGU-T-M, AGU-P, the most common problem is the burnout of a bimetallic plate, which is used as a sensitive element.
In Arbat and Orion, only a thermocouple and a thrust sensor, as well as an electromagnetic valve (rarely), can be replaced. The automation unit is practically beyond repair. In Arbat, the system shutdown button often breaks.
Typical problems for automatics SABC are damage to the membranes of the main valve, drying of the gland packing of the temperature controller, resulting in gas leakage. Impulse tubes, bimetallic plates, ball valves are subject to control.
In conclusion, I would like to emphasize once again that automation is designed to maintain the operation of heating equipment in a safe mode. Therefore, it is simply necessary for owners of gas boilers.
This video shows troubleshooting the AOGV boiler automation, a step-by-step assembly process and testing the result.
All modern heating installations using natural gas as an energy carrier have a high level of safety, which is achieved through the introduction of automation. They control and manage the process of operation of heating units. In this material, we will consider automation for gas boilers from the most famous manufacturers, which is most often installed on domestic and imported boilers.
Solenoid valve
The solenoid valve is a shut-off valve that directly affects the safety of the unit. It is mainly installed so that in the event of a malfunction, it closes the fuel supply. Emergency situations in the operation of gas heating can occur due to various factors:
- fuel pressure drop;
- lack of fluid in the system (you can check the joints, three-way valve and pipes);
- traction deterioration;
- gas leak.
Each of the above problems is dangerous for human life, and therefore the further operation of the system is unacceptable. That is why the solenoid valve works. Its original position is open. To close it, an electrical impulse is applied to it, coming from a thermocouple installed above the flame in the combustion chamber or on the chimney.
It must be said right away that this element rarely comes out of standing position, since it has great potential for use. Despite this, moments still happen.
There are two ways to check the operation of this valve:
- Fire. The used thermocouple is replaced with a new one. The automatic button is turned on. Next, the igniter is ignited and fire is brought to the end of the thermocouple. In this case, the automation should work.
- Instrumental. The sensor is removed from the housing and a repair contact is inserted. It is supplied with voltage from 3 to 6V. If the solenoid valve is in order, the automation will work. Otherwise, you need to replace this element.
Functions and principle of operation of safety automation
In accordance with regulatory documents, automation equipment for boiler plants must stop their operation by cutting off the fuel supply in the following situations:
- draft in the chimney is insufficient and there is a danger of burning;
- the gas pressure in the supply line is too low or, conversely, too high;
- the flame on the igniter went out.
The listed situations can lead to the main burner attenuation and gas contamination of the room, which is unacceptable. For this reason, gas boiler safety automatics must be installed on all old-style boilers, where it was not provided by the manufacturer. Although it is often cheaper to replace the heater than to purchase and install automation on the old one. In addition to preventing gas contamination of the room or waste, its function also includes maintaining the temperature of the coolant at a certain level set by the user.
To understand how the automation of a gas boiler works, we will briefly analyze its device. It should be noted that both foreign and Russian manufacturers use the same principle of operation in their products, although the devices may differ significantly in design.The most simple and very reliable are traditionally considered automatic gas valves from Italian manufacturers, so they are most common.
A prominent representative of such gas appliances is the Italian SIT automation, or rather, its most popular modification 630 EUROSIT, whose device is shown below.
All structural elements are placed in one building, to which gas pipelines are connected. In addition, a capillary tube from draft and temperature sensors (thermocouples), a gas pipeline for supplying an igniter and a cable from a piezoelectric element are connected to the device. Inside is a shut-off solenoid valve, whose normal state is “closed”, as well as a gas pressure regulator and a spring valve.
Any automatic gas boiler equipped with a EUROSIT combination gas valve or another must be started manually. Initially, the fuel path is blocked by a solenoid valve that opens by pressing the adjusting washer, after which the fuel fills the chambers of the device and goes to the igniter through a small gas pipeline. While holding the washer, we press the button of the piezoelectric device and set fire to the igniter, which heats the temperature-sensitive element for 10-30 seconds. That, in turn, generates a voltage that holds the solenoid valve open, after which the shim can be released.
Then everything is simple, we turn the washer to the required division and thereby open access to the fuel to the burner, which is independently ignited from the igniter. Since the automation of gas boilers is designed to maintain the set temperature of the coolant, human intervention is no longer required. Here the principle is as follows: when heated, the medium in the capillary system expands and acts on the spring valve, closing it when the high temperature is reached. The burner goes out until the thermocouple cools down and the gas supply is restored. You can learn more about the work of Italian SIT automation by watching the video.
Main types of solenoid valves
- Solenoid shut-off valve for use on pipelines through which only liquid media or gases are transferred. This equipment works as part of air conditioning, ventilation, oil products, gas and steam systems.
- Valves with pneumatic drive.
- Explosion-proof and intrinsically safe valves.
- Devices that allow you to control pneumatic actuators
- Valves for special purposes (solenoid solenoid valve that work with cryogenic working media, gas stations, vacuum plants).
- Electropneumatic distributors.
The manufacturers presented today create normally closed solenoid valves. In the presence of a manual cocking of the shutter, an automatic overlap occurs, which is triggered when a signal is received on the coil (electromagnet). All fuel solenoid valves are a tool to increase the safety of the facility, since in the presence of malfunctions and the operation of the equipment, they must be assembled.
Our company is actively working on the design and development of new modifications of solenoid valves. Call, contact, we are always ready to provide detailed advice on all questions.
A locking device that is used in LPG and allows you to shut off the gas supply while parking or while the car is running on gasoline (or diesel).
LPG equipment is installed in a car and gives you the opportunity to choose what fuel to drive on: gas or gasoline (diesel). Gasoline is getting more expensive day by day, and the number of gas stations is growing, and new modified LPG systems are appearing, the improvements of which make it possible to save money and be sure of the safety of yourself, passengers and cars.
The gas solenoid valve is also designed to purify gas from impurities using a filter, it is controlled both in manual and automatic modes (switching from gas to gasoline and vice versa).
