English isn't as paranoid as German about repeating words within a sentence -- or even a paragraph, as some people try to avoid.
In fact, in technical writing, it is undesirable to switch terminology. Item A remains Item A and doesn't switch at some point to Item B. There's absolutely no need to switch from "equipment" to "device" there. (In fact, I'd say that that would be bad form -- "equipment" and "device" are not necessarily interchangeable.) (Plus, the two uses of equipment wouldn't be as "piled up" on each other as "Gerät" is at the end of the German sentence (even without the mistaken repetition.)
However, it is often possible to reword a sentence to avoid the need for repetition (which, if done well, need not lead to confusion.)
One quick attempt (I don't have time to think of a more elegant solution at the moment): It must be kept within reach and remains with the equipment even upon its sale. (Some might argue that "its" isn't clear -- although the closest noun it refers to is "equipment," so that meaning is technically clear.
I don't particularly like beginning the sentence with "It" -- unless it's absolutely clear from the preceding context what "it" refers to. If, for example, you used "operating instructions" in a previous sentence to translate "Bedienungsanleitung," you could conceivably begin this sentence with "These instructions must...." (I know it sounds like I'm contradicting what I wrote above, but "These instructions" clearly relates to the previously mentioned "operating instructions" but in a shortened form.)
Edit: Bubb was faster.