This part is normally located at the bottom of the Chaffoteaux boiler and it's the part in the boiler that allows all the waste condensate water to exit the boiler out to the drains. Some Condensate Traps - Siphons have an electrical connection on them to monitor the level of the condensate water within it. If there is a blockage to the drains water can back up through the siphon into the boiler causing possible damage, this can't dhappen because when the siphon becomes full of water an electrical circuit is made which in turn stops the Chaffoteaux boiler from working.