York S1-024-27688-001 Switch

Hi, I was wondering what this low pressure switch (York S1-024-27688-001 Switch) is used for. I have one on my furnace and don't know why it is there as it is not come with it from the store.

It is a normally open single pole switch that will make contact when the pressue hits its set point. Power is cut off by this switch until the pressure is at / within the required setting.