Hey,
Ok so a quick look at the other mod, and I can see whats going on.
To borrow a phrase from Magic the Gathering, What DarkFrei is doing is a replacement effect! His mod, waits for an offshore pump to be built, builds his version on top, then removes the original created pump.
My mod listens for both creation and removal events, so is likely flip flopping getting ready to go when it sees the base version built, then shutting down when its immediately removed.
The fact its actually an "assembly machine" in code shouldn't matter, my offshore drain is actually a "pipe to ground" :D
Shouldn't be too hard to get this working, ill see what I can do for the next version, though DarkFrei will also need to update his mod for 1.1 when that releases to stable.