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Gas-fired boilers are one of the special equipment, which are explosive hazards. Therefore, all personnel who operate the boiler must be familiar with the performance of the boiler they are operating and relevant safety knowledge, and hold a certificate to work. Let’s talk about the regulations and precautions for safe operation of gas boilers!
Gas boiler operating procedures:
1. Preparation before starting the furnace
(1) Check whether the gas pressure of the gas furnace is normal, not too high or too low, and open the oil and gas supply throttle;
(2) Check whether the water pump is filled with water, otherwise open the air release valve until the water is filled. Open all the water supply valves of the water system (including the front and rear water pumps and the water supply valves of the boiler);
(3) Check the water level gauge. The water level should be in the normal position. The water level gauge and the water level color plug must be in the open position to avoid false water levels. If there is a lack of water, the water can be filled manually;
(4) Check that the valves on the pressure pipe must be opened, and all the windshields on the flue must be opened;
(5) Check that all knobs on the control cabinet are in normal positions;
(6) Check that the steam boiler water outlet valve should be closed, and the hot water boiler circulating water pump air outlet valve should also be closed;
(7) Check whether the softened water equipment is operating normally and whether the various indicators of the soft water produced comply with national standards.
⒉Start furnace operation:
(1) Turn on the main power;
(2) Start the burner;
(3) Close the air release valve on the drum when all steam comes out;
(4) Check the boiler manholes, hand hole flanges and valves, and tighten them if leaks are found. If there is leakage after tightening, shut down the boiler for maintenance;
(5) When the air pressure rises by 0.05~0.1MPa, replenish water, discharge sewage, check the test water supply system and sewage discharge device, and flush the water level meter at the same time;
(6) When the air pressure rises to 0.1~0.15MPa, flush the water trap of the pressure gauge;
(7) When the air pressure rises to 0.3MPa, turn the “load high fire/low fire” knob to “high fire” to enhance combustion;
(8) When the air pressure rises to 2/3 of the operating pressure, start supplying air to the warm pipe and slowly open the main steam valve to avoid water hammer;
(9) Close the drain valve when all steam comes out;
(10) After all drain valves are closed, slowly open the main air valve to fully open, and then turn it half a turn;
(11) Turn the “Burner Control” knob to “Auto”;
(12) Water level adjustment: Adjust the water level according to the load (manually start and stop the water supply pump). At low load, the water level should be slightly higher than the normal water level. At high load, the water level should be slightly lower than the normal water level;
(13) Steam pressure adjustment: adjust combustion according to load (manually adjust high fire/low fire);
(14) Judgment of combustion status, judging air volume and fuel atomization status based on flame color and smoke color;
(15) Observe the exhaust smoke temperature. The smoke temperature is generally controlled between 220-250°C. At the same time, observe the exhaust smoke temperature and concentration of the chimney to adjust the combustion to the best state.
3. Normal shutdown:
Turn the “Load High Fire/Low Fire” knob to “Low Fire”, turn off the burner, drain the steam when the steam pressure drops to 0.05-0.1MPa, close the main steam valve, manually add water to a slightly higher water level, close the water supply valve, and turn off the combustion supply valve, close the flue damper, and turn off the main power supply.
4. Emergency shutdown: close the main steam valve, turn off the main power supply, and notify superiors.
Things to note when operating a gas boiler:
1. In order to prevent gas explosion accidents, gas boilers not only need to purge the boiler furnace and flue gas channels before starting, but also need to purge the gas supply pipeline. The purging medium for gas supply pipelines generally uses inert gases (such as nitrogen, carbon dioxide, etc.), while the purging of boiler furnaces and flues uses air with a certain flow rate and velocity as the purging medium.
2. For gas boilers, if the fire is not ignited once, the furnace flue must be purged again before ignition can be carried out for the second time.
3. During the combustion adjustment process of the gas boiler, in order to ensure the combustion quality, the exhaust smoke components must be detected to determine the excess air coefficient and incomplete combustion. Generally speaking, during the operation of a gas boiler, the carbon monoxide content should be less than 100ppm, and during high-load operation, the excess air coefficient should not exceed 1.1~1.2; under low-load conditions, the excess air coefficient should not exceed 1.3.
4. In the absence of anti-corrosion or condensate collection measures at the end of the boiler, the gas boiler should try to avoid long-term operation at low load or low parameters.
5. For gas boilers burning liquid gas, special attention should be paid to the ventilation conditions of the boiler room. Because liquid gas is heavier than air, if a leak occurs, it can easily cause the liquid gas to condense and spread on the ground, causing a vicious explosion.
6. Stoker personnel should always pay attention to the opening and closing of gas valves. The gas pipeline must not leak. If there is an abnormality, such as an abnormal smell in the boiler room, the burner cannot be turned on. The ventilation should be checked in time, the smell should be eliminated, and the valve should be checked. Only when it is normal can it be put into operation.
7. The gas pressure should not be too high or too low, and should be operated within the set range. The specific parameters are provided by the boiler manufacturer. When the boiler has been running for a period of time and the gas pressure is found to be lower than the set value, you should contact the gas company in time to see if there is a change in the gas supply pressure. After the burner has been running for a period of time, you should promptly check whether the filter in the pipeline is clean. If the air pressure drops a lot, it may be that there are too many gas impurities and the filter is blocked. You should remove it and clean it, and replace the filter element if necessary.
8. After being out of operation for a period of time or inspecting the pipeline, when it is put back into operation, the vent valve should be opened and deflated for a period of time. The deflation time should be determined according to the length of the pipeline and the type of gas. If the boiler is out of service for a long time, the main gas supply valve should be cut off and the vent valve should be closed.
9. National gas regulations should be followed. Fire is not allowed in the boiler room, and electric welding, gas welding and other operations near gas pipelines are strictly prohibited.
10. The operating instructions provided by the boiler manufacturer and burner manufacturer should be followed, and the instructions should be placed in a convenient place for easy reference. If there is an abnormal situation and the problem cannot be solved, you should contact the boiler factory or gas company in a timely manner depending on the nature of the problem. Repairs should be carried out by professional maintenance personnel.
Post time: Nov-20-2023
