This is a Vacuum Pressure Switch for St. Croix pellet stove.
**If you have an older Hastings but it has a digital control board. You will use this part to replace the part number 80P52628-R.***
Instructions
Attach vacuum hose to white negative(-) port. The Black positive(+) port will not be used unless you have the Revolution Furnace. Blocking off/Plugging up the unused Black positive(+) port not necessary.