Slag Heater

Slag Heater is a building that consumes slag to produce Heat for the heat network in the direction it faces. It outputs 8 units of Heat to the facing Heat network while consuming slag as fuel. The block was added in Build 136; later adjustments removed an erroneous display of a 10-item capacity in the core database (Build 142) and increased its liquid capacity from 40 → 160 liquid units (Build 147). Slag Heater requires a steady supply of slag and must be oriented so its face connects to the Heat network or devices that use Heat.

Slag consumption scales with throughput and with how the heater is combined in setups such as Surge Crucible heating. When raising the efficiency of a Surge Crucible, the factory’s slag consumption increases accordingly. Example measured setups show required slag per second and pump throughput for different effective efficiency levels:

• At 110% efficiency: a setup using 1 Slag Heater and 1 Electric Heater requires about 84 slag/sec, roughly 1.05 pumps, corresponding to about 4.2 slag tiles feeding it.
• At 300% efficiency: a setup using 3 Slag Heaters and 2 Electric Heaters requires about 240 slag/sec, roughly 3 pumps, about 12 slag tiles.
• At 400% efficiency: a setup using 5 Slag Heaters requires about 360 slag/sec, roughly 4.5 pumps, about 18 slag tiles.

Practical notes for use and placement:

• Place Slag Heaters so their face connects directly into the Heat network or adjacent heat-consuming buildings for maximal transfer; they only output Heat in their facing direction.
• Provide continuous slag supply via conveyors, bridges, or pumps. Measured consumption for some setups is about 40 slag/sec (with a per-cycle figure noted as ~53.33 in certain timing contexts); plan transport and storage to match peak demand.
• Combine Slag Heaters with Electric Heaters when higher Heat output or higher effective efficiency is required; mixing multiple heater types changes total slag consumption and the number of pumps needed.
• The increased liquid capacity (from 40 to 160) changed how much liquid (if applicable in mixed-fuel setups) the heater can hold; verify your liquid logistics if you use slag in liquid form or use adjacent liquid-dependent systems.
• Monitor pumps feeding slag: round up pump counts because fractional pump requirements translate to additional physical pumps in-game.

Slag Heater is primarily used to supply Heat for high-temperature factories and processes; size your supply chain and heater count to match the Heat demand of downstream buildings and the chosen efficiency of those factories.