Step-by-Step Procedure and Standards for Water Quality Testing of Gas Boilers

Determination of Chloride Ion Content

Measure 100ml of boiler water into a 250ml conical flask, add 2-3 drops of phenolphthalein indicator, which should turn pink. Then titrate with sulfuric acid until colorless. Add 2-3 drops of potassium ferricyanide indicator and titrate with silver nitrate standard solution until a date-red color is obtained. Record the volume of silver nitrate consumed, multiply by 35.5 to obtain the chloride ion standard: chloride ion ≤ 400.

Determination of Alkalinity

Measure 100ml of boiler water into a 250ml conical flask, add 2-3 drops of phenolphthalein indicator, the solution turns pink. Titrate with the standard sulfuric acid solution until the color just fades, then add 2-3 drops of methyl orange indicator and continue titrating with sulfuric acid until it turns orange-red. Record the volume of sulfuric acid consumed; this value is equivalent to the alkalinity value.

Measurement of 3 Hardness

Pipette 100ml of boiler water into a 250ml conical flask, add a few grains of Lohmann T indicator, then add 2-3 drops of ammonia-ammonium chloride buffer solution. Titrate with EDTA standard solution until the solution changes from wine red to blue, and record the volume of EDTA solution consumed. This volume is equivalent to the hardness value of the boiler water.

Standard: Hardness: Steam oven less than or equal to 0.03 mmol per liter

Water heater 0.6 mmol per liter

Determination of pH Level

Use pH test strips to measure

Standard: pH Value: 10-12

Gas boilers have their own maintenance procedures, not just the maintenance of the boiler itself, but also the repair and maintenance of auxiliary equipment and accessories. The maintenance of a single gas boiler unit alone is a complex matter, as the boiler's structure is intricate, and only regular normal use and thorough post-maintenance can ensure a longer lifespan. Compared to the maintenance of more complex boiler types like circulating fluidized bed boilers and power station boilers, the maintenance of gas hot water and steam boilers is relatively easier due to the simpler structure of the boiler itself, but it is still much more challenging than that of ordinary machinery.

1. Cleanliness:

Open the burner door, remove the rear shell panel, and unscrew the boiler's side cleaning port screws. Clean the gas pipeline with a wire brush. Clean the combustion chamber with a soft-bristled brush. Remove the residue inside the boiler, screw the cleaning port screws back on, close the burner door, and check if the seal ring is intact.

2. Antifreeze

If the boiler is installed in an area with temperatures below 0°C, the following protective measures must be taken: If the boiler room is outdoors, lower the indoor temperature to 15°C or 18°C to keep the boiler running all day. If the room will be unoccupied for an extended period, drain the water inside the boiler.

3. Cathodic Protection

Boiler components are made of various materials, such as cast iron, copper, and aluminum. Cathodic protection measures must be taken to prevent electrochemical corrosion.

4. Wastewater Disposal

Bottom drainage of gas boilers can prevent smoke condensation. Smoke condensation occurs due to water content in the flue gas (diesel or natural gas) and low flue gas temperatures. Burning 1kg of diesel produces 1.04kg of water. Some of this water is vented out through the chimney, some is absorbed by the chimney walls, and the remainder settles at the bottom of the chimney. The amount of water produced is influenced by factors such as flue gas temperature (efficiency reaches 91% with flue gas temperatures at 170℃), the total surface area of the chimney, the material of the chimney, and the insulation of the chimney.

5. Burner Maintenance:

Maintenance of gas boilers and burners is best conducted after the heating season, rather than at the start of it. This is because combustion products can corrode the boiler and accumulate soot, so it's not advisable to allow the combustion products to linger in the boiler for too long.