Pellet boiler I/O module with numerous sensors and actors connected. Made by kwb in 2008. As seen on an Easyfire USP boiler. This I/O module uses 18 relays and three current transformers (the dark orange things sticking out). It has 11 temperature sensor inputs, 14 other inputs (rpm, analog, switches), and 20 power outputs. It is controlled over an RS-485 bus by the control module.
<a href="//commons.wikimedia.org/wiki/User:Phiarc" title="User:Phiarc">Phiarc</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>