Bosch Greenstar Boilers Installed at Elevation

The Bosch Greenstar Floor-Standing (FS) and Wall-Hung (WH) straight boilers and combi boilers are affected by higher elevations and thin air.  Input and output rates are reduced at higher altitudes due to thin air with reduced oxygen levels.  Some of the FS and WH units have a couple different fan speed adjustments that may help with the elevation.  Basically the Bosch Greenstar boilers will lose 3% for every 1000 ft of elevation.  No adjustment is needed up to 2,000' sea level.

The Larger Bosch Greenstar 151,000 BTU boilers both FS and WH units will not be effected by the fan speed adjustments and will be derated at 3% for every 1000 ft elevation.

All of the rest of the FS and WH straight boilers and combi boilers (57K BTU - 131K BTU) offer altitude adjustment which compensates for the effects of thin air, and are therefore NOT derated up to 6000 feet (1829 m). Above 6000 feet (1829 m) a rate of 3 % per 1000 feet (305 m) applies.  Please see the chart below and the fan speeds for adjustment.

Service function 0.d: Altitude adjustment:

For further help with altitude adjusments please call Bosch Greenstar Technical Support at 1-800-283-3787