Backdraft Reducer #9301BFP for Bosch Tankless Water Heaters

The Heat Fab backdraft reducer (9301BFP) is the preferred option for limiting backdraft for the Bosch Condensing tankless water heaters (see fig. 22).

Note: The following solution is available only for 3" diameter venting.

In cold climates, components of a tankless water heater can freeze and burst from negative draft. A leading cause of negative draft is combustion appliances in the building not being supplied with sufficient combustion air. A wood stove or furnace can pull its combustion air from the water heater‘s vent pipe, allowing the cold incoming air to freeze the cold water in the heat exchanger. The best prevention for this risk is two pipe venting which draws the appliance combustion air from outside creating a positive pressure inside the unit.

For this solution to be effective, the internal flapper must be 100% closed when the water heater is not running. Refer to Figures 24 and 25 for preferred installation positions in the vent system.

Installation considerations:
• Install damper per the supplied manufacturer‘s instructions.
• The damper is only to be used in the exhaust vent piping.
• Ensure directional arrow on damper label faces in the same direction as exhaust flow.
• If installed horizontally, the axis must be horizontal or slightly pitched up towards termination to ensure damper closes 100% when heater is not running.
• To allow accessibility, damper must not be installed in an enclosed section of vent pipe.
• Do not install damper in unconditioned spaces (e.g. attics) Condensation can build up while the heater is running which can later freeze and potentially block the flapper.

The Bosch C1210ES/ESC, C1050ES & C950ES are all approved to use the Backdraft Reducer. 

Phasing out of Bosch Therm 940ESO Outdoor Unit

Bosch is phasing out the Therm 940ESO model tankless water heater in Natural Gas, Part Number 7738000001 and Liquid Propane, Part Number 7738000002.

Bosch will continue to still make the Bosch Therm 940ES NG & LP tankless water heaters. The Bosch Therm Outdoor Kit (BTOK) will be sold as an accessory for outdoor installations.

The Phase out of the Bosch Therm 940ESO outdoor unit will be immediate. Please see the list below for model numbers, color changes by manufacturing date and BTOK model numbers.

Bosch Therm 940ES NG - #7703311076
Bosch Therm 940ES LP - #7703411073
(Gray Models, FD prior to FD420 - White Models, on or after FD420)

BTOK Outdoor Kit - Gray #7709003913
BTOK Outdoor Kit - White #7736502448

Please call Global Protankless Supply at 866-289-4652 for further questions or ordering.

Bosch Greenstar Intelligent Cascade Module (ICM) #7719003528

Bosch is always working on new ways to improve their products and has recently came out with an Intelligent Cascading Module (ICM) part #7719003528 for the Bosch Greenstar gas-fired wall-hung boilers.  The ICM modules are designed to control cascade systems.  A cascade system is a heating system where several smaller boilers are connected in parallel to achieve higher output.  The Bosch ICM modules are only suitable for controlling Bosch Greenstar boilers with BUS-enabled Heatronic 3 systems.

One Bosch ICM module can control up to 4 Greenstar boilers.  By conecting up to 4 ICM modules, up to 16 boilers can be linked to form a single cascade.  Depending on the heating system controls used, a cascade system with up to 4 or up to 16 boilers can be created.  The maximum number of boilers that can be connected and the number of ICM modules required for the different systems are shown in the table below.