Bosch AQ1 Discontinued

The Bosch AQ1 side wall power vent kit has now been discontinued for several years. It is now completely unavailable. The AQ1 vent kit was used for Bosch AquaStar 125B tankless water heaters that were vented horizontally out the side wall.

The current replacement for the Bosch AquaStar 125B is the Bosch Therm 520PN. The 520 PN uses the AQ4 side wall power vent kit for all horizontal venting installations. No power vent kit is required when venting the 520 series tankless water heaters vertically up through the roof.

The AQ4 cannot be used as a substitute side wall vent kit for any Aqua Star125 tankless water heaters. The Bosch AQ4 can only be used for the Bosch Therm 520 series and the older Bosch 1600 series tankless water heaters.

Please call us with questions at 888.726.9752.

Bosch Therm 520HN & 520PN Installed at Elevation

The Bosch Therm 520HN and the Bosch Therm 520PN can be installed at elevations for people with homes or cabins in Colorado, New Mexico, etc.  The Bosch 520HN & 520PN are natural drafting units and require a 6" galvanized type B-vent and must vent vertical for a minimum of 6' to the rain cap for all elevations over 2,000'.

Gas pressure is dependent upon the gas type whether it is Natural Gas (NG) or Liquid Propane (LPG) and also the length of the gas line.  See sizing charts in the installation manual for the heaters.  The Bosch 520HN & 520PN can be installed above 4,500' elevation but the unit would have to have the gas pressure adjusted using a manometer to compensate for the air and gas mix at the high elevation.  Please see the insert below for more details.

Cutting the gas pressure back as per the chart above is called "de-rating" the burner.  Elevations above 2,000 ft require the Bosch tankless water heater to be de-rated 4% for every 1,000 feet.  Basically you will loose 4% of your heating capacity for every 1,000 ft.

Bosch 660EF / 660EFO Tankless Water Heater Sale

GlobalTowne.com is pleased to announce a special sale on the Bosch Therm 660EF / 660EFO tankless water heaters.

GlobalTowne has a large quantify of the Bosch 660EF indoor tankless water heaters and 660EFO outdoor tankless water heaters and we are currently offering these heaters at special low prices.

If you are installing the Bosch 600EF indoor water heater you will need to vent it with 3" single wall stainless steel venting. We carry Z-Flex-Z-Vent 3" stainless steel category III vent pipe. You will also need the Z-Flex 2SVSWB03 Bosch 660EF adaptor. We have worked closely with Z-Flex to develop this adaptor. Our Bosch 660EF adaptor is the only one that will work properly with the Bosch 660EF heater.

The Bosch 660EFO outdoor tankless water heaters do not require any venting.

The Bosch 660EF / 660EFO tankless water heaters are 140,000 BTU maximum input heaters. They are very compact and are capable of providing hot water for one shower and a sink at the same time.

Steve