BS writes - virtually all injected engines also have throttle body heaters.
I assume that you are referring to road vehicle injection systems?
I've installed a couple of injector set-ups (one a standard Bendix, the other Airflow Performance) on Lycomings and have not been aware of any hot water plumbing or lecky connections!
I believe that induction icing in an injected aero-engine is unheard of - prove me wrong and I'll happily get the beers in.
Stik