If venting horizontally, you will need the 250SX Horizontal Vent Kit (AQ3). This kit can be purchased from the same dealers that sell the Bosch AquaStar 250SX. The kit includes the following components:

  • 1 - 3” Adjustable Adapter
  • 1 - 3” x 90° Elbow
  • 1 - 3” Wall Thimble
  • 1 - 3” Exhaust Vent Hood with 10” Sleeve
  • 1 - 3” x 10’ Aluminum Flex Pipe – Inlet Air
  • 1 - 3” Intake Vent Hood with 10” Sleeve
  • 2 - 3” Gear Clamps



The exhaust vent pipe and the combustion air pipe each have a maximum length of 26 feet (8 meters) with one elbow. For each additional elbow after the first elbow you must reduce 2.5 feet from the total length. A maximum of 3 elbows on each pipe is allowed.

Download the AQ3 Horizontal Vent Kit Manual (PDF)

Note: Depending upon your specific installation, the AQ3 Horizontal Vent Kit may not meet all of your venting needs.


If you will be terminating the vent pipe from the Bosch AquaStar Model 250SX vertically up a chimney,
the AQ3 Vent Kit is not required. PLEASE NOTE: Additional venting components can be obtained by Clicking Here.