Not only do we have to flush out those wet returns, but we also need to flush out the boiler annually. It’ll have just as much gunk in it, and it’s no good leaving it there. But this typically isn’t done either because, once again, there’s no way to do it. Just filling and draining the boiler with the normal water fill hasn’t the pressure needed to entice the gunk to leave. And that’s why we install King Valves on all of the steam supplies and returns. Now, come maintenance time, we can close all the valves, fire the boiler, and build up some real pressure. Then we hook up a hose to a drain, open the drain, and viola! -that gunk is moving like you-know-what through a goose. Of course, if you wait 10 years to have us out to do the maintenance, this might not work so well. But if you call us every year, it works like a charm. So call already. That’s why we put the valves there!