3 Pass, Gas fired Automatic Hot Water Generator Comprises of a nest of closely wound helical concentric coil to give three passes of flue gas and fabricated out of HIGH HEAT RESISTANT BOILER TUBES suitable for high temperature service. The coil is housed concentric in M. S. Shell. Heater shell is directly welded to a sturdy M.S. base frame. Front door is provided on hinge for ease of maintenance.