For the past couple years I have been getting iron rust on concrete and bricks etc. from my lawn sprinkler system. Only parts there that are iron is the pump itself and one length of galvanized pipe--rest is PVC.
Question is--the pump has two plugs to drain in cold weather, one at bottom of pump--second is close to the top but still on face of pump. That top plug goes into a cavity inside the pump that appears to be away from the main water storage section. What is this extra "section" inside the pump?
Also--would this "section" have more suction than the lower main section that supplies the pump ?