Sootblowers are devices that remove ash and carryover deposits from the inside of a furnace. During operations, combustion gasses are formed and they flow towards the back end of the furnace. The composition of the flue gas may have solid particles as ashes, products of the fuel combustion, and also un-burnt fuel as it is stripped by the velocity of the flue gas flow. Some of these are solid particles that may deposit on boiler tubes or other internal components such as superheaters, generating bank, economizers, etc. Others may be components in gaseous state but as the flue gas cools down as it travels through the furnace, some of these products may become liquid or even solids and may also precipitate or deposit on these surfaces.

Deposits significantly inhibit heat transfer from the fuel combustion into the water or steam tubes. Solid metal can conduct and transfer heat very well but a deposit acts as a layer of insulation and thus inhibits this transfer. As this happens, less heat produced by the combustion is transferred into the water or steam and more is retained in the flue gas. This becomes an expensive situation that is not efficient. Sootblowers are devices that attempt to remove these deposits during the operation.

All sootblowers operate on the principle of blowing a steam or air through a nozzle, under higher pressure and thus velocity, with an attempt to knock the deposits down. The deposits then either fall back into the lower furnace, or into ash hoppers, depending on the location of the sootblower and the design of the furnace.

There are 3 types of most common sootblowers:

1. Wall Blowers also known as IRs (Insertable Rotating)
   
2. Long Retractable Soot Blower (LRSB) or IK (Insertable Kinetic) - (Most common in Kraft Liquor Recovery Boilers)
   
3. Stationary sootblowers (e.g. G9B)
   

During a shutdown, all sootblowers should be locked out and as such safe to access and inspect. Gloves are recommended for inspection. Grease, oil, sharp surfaces are commonly encountered around sootblowers.

During an operation, increased caution is required as sootblowers can be quite dangerous. They use a medium such as an air or steam under high pressure. Sootblowers are remotely operated and start without warning. It is not uncommon to have leaking flanges and wallboxes and a hot steam can start flowing out of the sootblower components unexpectedly. Certain sootblowers also have rotating equipment. Never walk under or near sootblowers while the boiler is in operation.