Circulating Hot Water Systems for Contractors

Circulating hot water systems distribute hot water to faucets on a “closed loop” system that circulates the water to deliver it on demand. The 2009 IECC mandates a minimum of R-2 insulation for piping in cir-culating hot water systems. The code also stipulates an “automatic or readily accessible manual switch” that controls the hot water circula-tion pump.