ON/OFF switch for circulators. Allowable? Type to use?

I have 4 Grundfos circulators on my heating system. When one goes, every few years it seems, it makes a helluva noise. If it's in the middle of the night, I can't get a plumber right away, or don't want to pay off-hour rates. To get rid of the noise I have to shut down the whole system. What I'd like to be able to do is shut down the bad circulator only, until I can have it replaced. Can I wire up a simple switch, one per circulator, to do that? Any code issues? What type switch would you recommend? Today I opened up a little electical box and unwired the bad circulator, but I'd like to make it easier, in case it happens when I'm out and my wife has to stop a circulator from squealing.

Thanks,

Tom