.Just ask yourself the reverse of that question. Why mount it on a shelf and take up very valuable storage space, when you can mount it up and out of the way. When we load out one of these units to meet the Federal requirements, there is no left over space to play with.
However, looking at your picture, it could have been mounted on top of the shelf it's mounted to now, but then it would be in the way of getting to the electrical components and wiring if they needed to be serviced.
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Well, there are 3-4 components and I'm going to move them to the left and move the compressor up.
There is a screen in front of the opening and the whole thing will be secured and much safer.
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