Unknown horror movie

When I was a kid I was sleeping with the TV on and when I woke up I saw the ending of this film and recently I remembered that I never found out what the name was. There was this girl and two young kids running from a monster in what I'm assuming was the high school of the girl. The monster had a gutural sound when moving and was slow paced, the girl had the chance to hide the little kids in what I remember as a chapel (something similar as the reasoning was that the monster couldn't enter) after that the girl lures the monster into the kitchen and uses the gas system to make and explosion and burn it alive, then a demonic voice and face appears in the flames and tell her that it will comeback one day to torment her. The movie had an 80s look and I thought it was Hellraiser but it wasn't.