Operates but does not heat

Found blowup drawings inside unit, which helped identify what I had to remove. Had neighbor assist in lifting unit from wall mount, unit slides easily from rails once top bolts are removed. Pay attention to where all the screws go as you remove them, some inside assemblies will have to be removed or loosened. A good guideline to go by is all black screws hold internal assemblies, the bronze screws go in the back side and the chrome screws go on top, sides, and front of the unit. I was able to lift unit back on rails without any assistance.