When the fireside of a boiler is properly cared for, efficiency and boiler life will be increased. If it is mismanaged and not cared for properly, soot and other non-combustibles can start to collect in the boiler’s systems.
This can reduce the amount of heat transferred to the water and increase the fuel consumption. Most states require that the fireside and waterside of a boiler be inspected once a year, but even if it’s not a state requirement, inspecting the fireside should be a regular habit.
Here are some things to check during maintenance: the type of fuel, the load the boiler is under, and how efficient the boiler is when combustion is taking place. Byproducts from unclean fuel can combine with water in the air to create corrosive acids that eat away at the metal in the fireside. If the combustion is poor, the boiler will burn far too much fuel to maintain proper efficiency levels.
It is important to take into consideration the burner and controls. A log should be kept in order to monitor combustion parameters. If a steady increase in stack gas temperature occurs, then it is time to check for soot deposits in the fireside. Keeping a good record of operations will help you identify the time when the boiler is running out of ”normal” operating conditions.
Be sure to visually check the gaskets used to seal the fireside door. Replace the door gaskets at least once a year or when the fireside is shutdown for maintenance and the door is open. If the gasket that seals the door is not working properly, it could result in gasket burning, steel door deformation, loss of efficiency and above all‚ it could cause a safety hazard.
Tub Sheets, Tubes and Furnace
When inspecting a fireside and its tubes, be sure to look for any sign of blisters of other signs such as “pock-marks.” If evidence occurs, it is possible that corrosion is emerging due to condensation with the flue gasses and forming acidic solutions.
A remedy for corrosion is to set the boiler controls to the longest “on” time. This change will prompt the boiler to cycle less frequently and helps reduce condensation. Boiler water should be maintained at a minimal temperature of 170°F to help keep water vapor from condensing in the flue gas.
Cleaning the Tubes
When inspecting the tubes, look for soot deposits or any kind of white streaks that indicate leakage. A unit that is properly adjusted and well-designed should never need the tubes cleaned. However, the length of time for cleaning the tubes varies with the type of fuel that you use in a unit. In some situations, it may be required that you clean the tubes once or twice a week, an example of this is when firing #6 oil. If a layer of soot is noticed in a short period of time, this indicates that the fuel-to-air mixture is running too rich, so there is more fuel than air. This causes the fuel to burn inefficiently, but it can be remedied by adjusting the ratio between fuel and air. If trying to save time on an inspection, try installing a thermometer in the flue gas vent outlet on the boiler. If there is a rise in temperature, it means that the tubes my be collecting soot and need to be closed.
Information was published online by Power Plus International: “Tips From The Boiler Man.”