A gas to gas heat exchanger 110 is equipped with a heat transfer element cleaning system 160, effluent collector hopper 162 and effluent collector hopper cleaning system 164. The heat transfer element cleaning system 160 is useful to remove accumulated substances from the heat exchanger 110 heat transfer elements 134. The effluent collector hopper 162 is useful to capture a cleaning fluid used to remove accumulated substances from the heat exchanger 110 heat transfer elements 134. The effluent collector hopper cleaning system 164 is useful to remove accumulated substances captured with the cleaning fluid from the effluent collector hopper 162 to prevent clogging thereof.
