Editing Boiler (section)

==Accessories==
[[Image:Jämsänkoski pulp mill boiler.jpg|thumb|A boiler of [[Jämsänkoski]]'s pulp mill with calorisator in 1938]]

===Boiler fittings and accessories===
* [[Pressuretrol]]s to control the steam pressure in the boiler. Boilers generally have 2 or 3 pressuretrols: a manual-reset pressuretrol, which functions as a safety by setting the upper limit of steam pressure, the operating pressuretrol, which controls when the boiler fires to maintain pressure, and for boilers equipped with a modulating burner, a modulating pressuretrol which controls the amount of fire.
* '''[[Relief valve|Safety valve]]:''' It is used to relieve pressure and prevent possible [[boiler explosion|explosion of a boiler]].
* '''Water level indicators:''' They show the operator the level of fluid in the boiler, also known as a [[sight glass]], [[water gauge]] or water column.
* '''Bottom [[Boiler blowdown|blowdown]] valves:''' They provide a means for removing solid particulates that [[condense]] and lie on the bottom of a boiler. As the name implies, this valve is usually located directly on the bottom of the boiler, and is occasionally opened to use the pressure in the boiler to push these particulates out.
* '''Continuous blowdown valve:''' This allows a small quantity of water to escape continuously. Its purpose is to prevent the water in the boiler becoming saturated with dissolved salts. Saturation would lead to foaming and cause water droplets to be carried over with the steam – a condition known as [[Priming (steam engine)|priming]]. Blowdown is also often used to monitor the chemistry of the boiler water.
* '''Trycock:''' a type of [[valve]] that is often used to manually check a liquid level in a tank. Most commonly found on a water boiler.
* '''Flash tank:''' High-pressure blowdown enters this vessel where the steam can 'flash' safely and be used in a low-pressure system or be vented to atmosphere while the ambient pressure blowdown flows to drain.
* '''Automatic blowdown/continuous heat recovery system:''' This system allows the boiler to blowdown only when makeup water is flowing to the boiler, thereby transferring the maximum amount of heat possible from the blowdown to the makeup water.  No flash tank is generally needed as the blowdown discharged is close to the temperature of the makeup water.
* '''Hand holes:''' They are steel plates installed in openings in "header" to allow for inspections & installation of tubes and inspection of internal surfaces.
* Steam drum internals, a series of screen, scrubber & cans (cyclone separators).
* '''Low-water cutoff:''' It is a mechanical means (usually a float switch) or an electrode with a safety switch that is used to turn off the burner or shut off fuel to the boiler to prevent it from running once the water goes below a certain point. If a boiler is "dry-fired" (burned without water in it) it can cause rupture or catastrophic failure.
* '''Surface blowdown line:''' It provides a means for removing foam or other lightweight non-condensible substances that tend to float on top of the water inside the boiler.
* '''Circulating [[pump]]:''' It is designed to circulate water back to the boiler after it has expelled some of its heat.
* Feedwater [[check valve]] or clack valve: A non-return stop valve in the [[Boiler feedwater|feedwater]] line. This may be fitted to the side of the boiler, just below the water level, or to the top of the boiler.{{sfn|Bell|1952| page=35}}
* <!--(i) [[Top feed]] redirects here. (ii) Need to duplicate wikilinks, since reader may not read the 'feedwater check valve' line having been redirected to this section. -->Top feed: In this design for feedwater injection, the water is fed to the top of the boiler. This can reduce boiler fatigue caused by thermal stress. By spraying the feedwater over a series of trays the water is quickly heated and this can reduce [[limescale]].
* '''Desuperheater tubes or bundles:''' A series of tubes or bundles of tubes in the water drum or the steam drum designed to cool superheated steam, in order to supply auxiliary equipment that does not need, or may be damaged by, dry steam.
* '''Chemical injection line:''' A connection to add chemicals for controlling feedwater [[pH]].

===Steam accessories===
* Main steam stop valve:
* [[Steam trap]]s:
* Main steam stop/check valve: It is used on multiple boiler installations.

===Combustion accessories===
* Fuel oil system:fuel oil heaters
* Gas system:
* Coal system:

===Other essential items===
* [[Pressure measurement|Pressure gauges]]:
* [[Boiler feedwater pump|Feed pumps]]:
* [[Fusible plug]]:
* Insulation and lagging;
* Inspectors test pressure gauge attachment:
* Name plate:
* Registration plate: