• 85% AFUE efficiency
• Atmospheric combustion
• Chimney or horizontal vent venting
• Inducer fan and gas valve modulate for operation between 33% and 100% of capacity for fuel economy
• Advanced controls - digital display with temperature indication, diagnostics and status symbols showing - heating mode, burner on and burner modulation level, DHW mode
• Durable lightweight one-piece steel jacket
• Dedicated DWH connections for adding an indirect water heater

• Includes Wall mount bracket
• Boiler control module - automatic line VAC age/intermittent direct spark ignition/modulating with a 5:1 combustion turn down ratio
• User display interface - easy programming with text display, outdoor temperature sensor included
• Heat exchanger - high grade 316L/444 stainless steel fin coil with flame sight glass
• Built-in primary and secondary manifold piping and pump
• Combustion - gas valve with premix venture and blower, durable stainless steel mesh modulating burner with 5:1 turn down ratio, flame sensor and LP conversion kit included
• Low VAC age electrical terminal strip, high VAC age junction box and transformer
• Factory installed probe-type low water cut-off with test feature
• 30 psi safety relief valve, boiler drain valve and condensate drain with built in trap
• 150 psi maximum allowable working pressure
• 1/2" gas connection
• Low maintenance, self-cleaning
• Approved for PVC, CPVC and polypropylene venting
• Designed in the US

Bosch ZWB42-3A