Unintended ignition of unburned combustion gases in the fire box is possible. Leaking fuel valves can also be the cause of these accidents. If the operator notices any gas odor the boiler should be shut down and the fuel supplier called immediately. Water Treatment Basics Boilers are filled with water that contains naturally occurring impurities. Common impurities such as calcium, magnesium and oxygen can, if they are not controlled, effect boiler performance and durability.
All water contains dissolved minerals such as calcium and mangnesium.
If these minerals are allowed to reach high enough levels in the boiler water they will come out of solution and form as a hard shell on the hot surfaces of the boiler. This hard shell is called scale and is often found on the outside of the fire tubes. Scale insulates the heating surfaces recducing the ability o fthe fire tubes to transfer heat from the hot combustion to the boiler water. High stack temperatures or ruptured fire tubes are common problems related to scale build up. Boiler water also contains dissolved gases such as oxygen or carbon dioxide.