I had a similar situation with the last pool I built.

The contractor arranged for plaster, but the plaster job was bad, and he hadn't finished several other things. I had trusted him with a "final payment on day of plaster" clause but I refused to pay more than half of the full amount until the problems were fixed. He went ballistic.

The next day he showed up with the police to try to remove the pool equipment from our yard, as per the kind of language you're talking about. When he told the police we were holding "his equipment," they thought he meant his tools and construction equipment. When we pointed out that it was installed pool equipment for which we had already paid, the police (somewhat chagrined) backed off. We told the police we were willing to pay half of the remaining amount and the other half as soon as the problems were fixed - I actually had the check in my hand. The builder refused.

Of course, he had to take us to court to try to realize on what was, effectively, a security interest in the equipment. He didn't hire a lawyer up front so he filed the wrong kind of lawsuit - which as a lawyer I was able to recognize and promptly remove it to a more senior court with a much more expensive, and longer, litigation process. He also failed to file a mechanic's lien, so I published the required notice of completion and when the time period was up he couldn't do that. By the time he actually consulted a lawyer it was too late.

After over a year we settled and he only got part of what he wanted. He never did finish - we had to hire someone else to do it.

The moral of the story is, consult your lawyer, listen to what he or she has to say, and don't be bullied. The contractor can't just show up and start removing pool equipment. You can have him arrested for trespassing if he does so without a proper court order.