Bosch 8737707231 Heat Exchanger Block

- Cast aluminum heat exchanger block for compatible HVAC systems.

- Transfers burner heat into the circulating water supply.

- Single-piece cast aluminum construction for efficient heat transfer and durability.

- Internal coiled water passages positioned directly in the combustion gas path.

- Maximum allowable working pressure of 50 psi on water.

- Maximum water temperature rating of 250°F.

- Minimum relief valve capacity of 155 lb/h.

- Complete service kit with gaskets, seals, and condensate collector base.

- Includes ignition electrodes and sensor for a full section rebuild.

- Alternate part number 8-737-707-231.

The Bosch 8737707231 Heat Exchanger Block is the central heat transfer component in compatible HVAC systems, where it takes heat from the burner and passes it into the circulating water the unit uses to deliver warmth throughout the space. Its body is a single piece of cast aluminum, a material chosen for how efficiently it moves heat across its walls and how well it stands up to constant heating and cooling cycles, and the internal coiled water passages sit directly in the path of the hot combustion gases so very little heat is lost. On the water side, it is rated for a maximum working pressure of 50 psi and handles temperatures up to 250°F, with a relief valve capacity of at least 155 lb/h. It comes as a complete service kit that includes the gaskets, seals, condensate collector base, ignition electrodes, and sensor needed to fully rebuild this section, giving a technician everything required to return the system to proper operating condition.