Needing help to safely remove floor heater

[Dmac101]

We are trying to uninstall the floor heater (not working) which came with our 2005 Ford E-450 cutaway shuttle bus. It's bolted into the floor in the back right corner, and pretty big, so we need to take it out for that precious storage space. It's of course connected to tubes and wiring, and we want to ensure we remove it correctly and safely.

The heater is a Hoseline Inc. HU5100 model heater.

Thanks in advance!