The boiler accepts the following items as fuel:
The boiler has a minimum temperature of 20 and a maximum temperature of 500. Every 45 ticks the temperature of the boiler decreases by 1. Every 12 ticks 1 energy is consumed from the current fuel and raises the temperature by 1. However, if the boiler is at maximum temperature, it will not consume fuel to heat itself further. This means that when heating up, a lump of charcoal will only last 96 seconds, but when the boiler is at max temperature, a lump of charcoal will last 360 seconds, equating to 43200 Liters of steam.
The boiler can hold 16,000 Liters of steam and 16,000 Liters of water. As long as its temperature is above 100, every 25 ticks it will consume 1 Liter of water and produce 150 Liters of steam, equivalent to 6 mB/t of steam. Temperatures above 100 do not affect steam production. The Boiler will attempt to output steam from all of its sides except the bottom. However, it will accept water piped in from below, allowing water pipes to be safely placed below a line of boilers. If the steam tank fills, 1/4th of its capacity will be discarded and a smoke particle and hiss sound effect will be produced as an alert.
Water can be added to the boiler by right clicking on the machine with water buckets, or by placing any sort of cell with water in the water input slot in the GUI. Like all GregTech machines, it will give the empty cell back. If the temperature is above 100 and the boiler runs out of water, adding water will cause an explosion, so wait for it to cool off first.
Changes in Unofficial
In GregTech 5 Unofficial version 5.09.16, a change was made to the Small Coal Boiler. As of this version, fuel cannot be inserted and Ashes cannot be extracted via automation; it must be done manually by a player. Water can still be piped in.