Central Heating Unit problem?

I think i have a big problem with my central heating unit.It's been almost a week since it started making large explosions.The unit is located outside the house,but the explosions are so loud that i can hear them clearly.I went inside hours before to check what's going on.The unit was turned off,so i decided to restart it.For some seconds it was behaving normally until i heard the unit giving spark so as to ignite the mixture.Then,a loud explosion happened.I noticed that it happened near the induction area.I also realized that this has happened lots of times with equal force,because the hose was broken and had fallen off the ceiling where it was nailed.The unit uses LPG,not petroleum,that's why i am afraid.Now,i understand that it must be wrong mixture adjustment or misfiring.My question is: Is it safe to leave it turned on? It's cold and that's why i haven;t turned it off