I see what you are saying...and that does make more sense. No, getting to the back of the heater is even harder than getting to those pipes at the front of the pictures. I don't think my arms are long enough! The air compressor method is looking more viable, at this point.
I must know someone with a compressor. Or maybe I can buy something small enough to do the job, and yet not take up too much space.
Time to look at more YouTube videos!