Device:Steam Boiler

└ Module: Steam


A 12 cubic meter High Pressure Boiler (also called a '12 HP') At the heart of many industrial centers you will find a tentacled monster of a machine called a Steam Boiler. These machines can produce enough Steam to meet the energy needs of any complex. They may appear daunting at first, but our experts are here to help you install your own!

Now when building a Steam Boiler, the first layer put down must be the Firebox. We presently offer two types of Fireboxes. Solid Fueled, which burns normal furnace fuels such as Charcoal or Coal Coke, and Liquid Fueled, which uses liquid fuels such as Creosote Oil, Bio-Fuel, and good old fashioned Fuel.

There are three base sizes of Steam Boiler: the small 1×1 Boiler, the workhorse 2×2 Boiler, and the excessive 3×3 Boiler.

Once you've laid down the Firebox, you must build a Boiler Tank above it. Boiler Tanks come in two varieties: Low Pressure and High Pressure. The difference being that High Pressure Boiler Tanks produce twice the steam, but the Low Pressure Boiler Tanks are generally more efficient.

Each cubic meter of Low Pressure Boiler Tank produces 10 Steam/tick which is enough to run a single Hobbyist Steam Engine at full capacity or a Commercial Steam Engine at half capacity, basically 2 MJ/t. Each cubic meter of High Pressure Boiler Tank produces 20 Steam/tick, sufficient to run a Commercial Steam Engine at full capacity or an Industrial Steam Engine at half capacity, basically 4 MJ/t.

The larger the Steam Boiler, the more efficient it is in terms of fuel usage. You will be generally better off building a single large Boiler instead of several small ones. The caveat being that its better to build Low Pressure Boilers rather than High Pressure if you want maximum fuel efficiency for short runs (where the boiler doesn't reach maximum temperature). If you're running your boilers round the clock, you get exact same amount of steam per unit of fuel.

The size of the tank you can build depends on the size of the Firebox. A 1×1 Firebox can only handle a single cubic meter tank. The 2×2 can handle 8 or 12 cubic meters of Boiler Tank. And finally, the massive 3×3 can handle 18, 27, or 36 cubic meters of Boiler Tank.

Once you've built your Steam Boiler, you will need to provide it water and fuel. A word of warning, you must supply a constant steady stream of water to the Firebox (not the Tanks) or you run the risk of a massive Boiler explosion. Introducing water to a hot and dry Boiler is exceptionally dangerous. That said, Boilers are pretty safe so long as the water supply is constant.

When first heating up a boiler, they are very inefficient and will use up to 8x more fuel than when at max heat. It is generally recommended that you leave your boiler running all the time rather than shutting it down when not in use. Especially the larger Boilers since the heat up time is dependent on size.

When attaching Steam using devices to the Boiler, it can be done in two ways. The recommended method is using liquid pipes from our partner company BuildCraft, Inc. , but it is also possible to attach the devices directly to the Boiler. For those using pipes, Gold Pipes are heavily recommended and Wooden Pipes are NOT required or recommended. For those curious, normal pipes can move 10 Liquid Per Tick and Gold Pipes can move 40 Liquid Per Tick.


  • Rebalanced in
  • Liquid Fueled Firebox added in
  • Added in version



  • Steam/tick = ( 10 LP or 20 HP ) * numTanks * heat/maxHeat
  • 10 RF = 5 Steam
  • 160 mB of Steam per 1 mB Water
  • fuel used per tick = ( ( 8 - ( numTanks * 0.1 ) + ( 0.8 * heat/maxHeat ) + ( 4 * maxHeat/1000 ) ) * numTanks ) / ticksPerCycle
  • maxHeat = 500 for Low Pressure and 1000 for High Pressure
  • ticksPerCycle = 16 for Low Pressure and 8 for High Pressure
  public double getFuelPerCycle(int numTanks) {
      double fuel = Steam.FUEL_PER_BOILER_CYCLE;
      fuel -= numTanks * Steam.FUEL_PER_BOILER_CYCLE * 0.0125F;
      fuel += Steam.FUEL_HEAT_INEFFICIENCY * (getHeat() / getMaxHeat());
      fuel += Steam.FUEL_PRESSURE_INEFFICIENCY * (getMaxHeat() / Steam.MAX_HEAT_HIGH);
      fuel *= numTanks;
      fuel *= efficiencyModifier;
      fuel *= RailcraftConfig.fuelPerSteamMultiplier();
      return fuel;
  public static final float COLD_TEMP = 20;
  public static final float BOILING_POINT = 100;
  public static final float SUPER_HEATED = 300;
  public static final float MAX_HEAT_LOW = 500F;
  public static final float MAX_HEAT_HIGH = 1000F;
  public static final float HEAT_STEP = 0.05f;
  public static final float FUEL_PER_BOILER_CYCLE = 8f;
  public static final float FUEL_HEAT_INEFFICIENCY = 0.8f;
  public static final float FUEL_PRESSURE_INEFFICIENCY = 4f;
  public static final int STEAM_PER_UNIT_WATER = 160;
  public static final int STEAM_PER_10RF = 5;

More Information

Fuel Values


  • Nearly anything that burns in a Furnace may be used to feed a Solid Fuel Firebox.
  • Bucket of Lava = 1000
  • Charcoal = 1600
  • Forestry Peat = 2000
  • Coal = 3200
  • Coal Coke = 6400


  • Lava is not a valid liquid fuel, this is intentional.
  • Creosote Oil = 3200
  • Forestry Bio-Fuel = 32000
  • BuildCraft Fuel = 96000


Solid Fueled Firebox

Liquid Fueled Firebox

Low Pressure Boiler Tank

High Pressure Boiler Tank


Tutorial… complete with explosions!




device/steam_boiler.txt · Last modified: 2015/05/30 01:01 by
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