WATER HEATER WITH REHEATING FUNCTION

摘要

PROBLEM TO BE SOLVED: To provide a water heater with a reheating function that can securely clean piping of a reheating circulation circuit after condensate generated in a heat exchanger for recovering latent heat is discharged to the reheating circulation circuit.SOLUTION: Condensate drain means 40 includes: a recovery tray 41 disposed below an auxiliary heat exchanger 8 for recovering latent hear to recover condensate dropping down from the auxiliary heat exchanger 8; a drain circuit 42 connected between the recovery tray 41 and a reheating circulation circuit 20; and a drain tank 44 installed in the drain circuit 42. Control means 60 executes storage of condensate in the drain tank 44 and discharge of the condensate from the drain tank 44 to the reheating circulation circuit 20. After discharge of the condensate is completed, the control means 60 supplies cleaning water comprising predetermined amount of water or hot water from a hot water supply circuit 10 through a hot water filling circuit 30 to the reheating circulation circuit 20 to clean piping of the reheating circulation circuit 20. While the piping cleaning is being executed, if interruption for hot water supply occurs, the piping cleaning is interrupted, and after completion of the hot water supply, the piping cleaning is performed until the cleaning water reaches predetermined amount.