I have the exact same water heater on my cart. It works great and will heat the water up very hot and quick. I have never had any trouble out of mine. It didn’t seem like it took very long to purge the system but my tank is right next to it. When it lights you will know it and there is some heat that comes out of the top. I’m not sure if it would do anything to the pipe or not. I would think that you could just wrap it with the reflective insulation type material and it would be enough to shield it. I have something similar between my steam table and cooler with no problems. It holds ice all day with very little melting.