Fire Door Closing Systems : Pulley and Weight

Chris+s is correct about the door holder operation. The 972S is made for heavier doors and is rated at 75 pounds holding force. Might need a really good yank.

If an electrical manual release is still desired, it is quite easy. Since the holder releases the door on power loss, all that is needed is a normally closed momentary switch in series with the holder. Push the button, holder looses power, and the door closes.