Gas Dryer - Adjusting for Elevation / How to Derate

The Installation Instructions for a Gas Dryer will have a note about adjusting for elevation. The note will typically say:

 

ADJUST FOR ELEVATION

"Gas clothes dryers input ratings are based on sea level operation and need not be adjusted for operation at or below 2000 feet elevation. For operation at elevations above 2000 feet, input ratings should be reduced at a rate of 4 percent for each 1000 feet above sea level."

 

This same note may appear in the LP Gas Conversion Kit instructions for the Gas Dryer.

 

The owner or installer does not have to do anything special. You do not make an adjustment on the gas valve or have to install a different gas orifice for use at the higher elevation. You are informed through this note that the input rating of the dryer is not the one shown on the dryer rating label if the dryer is installed above 2000 feet. It will be lower. In order to know how low it will be, you will need to reduce the expected BTU rating by 4% for each additional 1000 feet above sea level. Since the BTU rating will be lower, the drying cycle time will be longer.

 

In summary, an adjustment shouldn’t be done in the gas valve, but in the expected BTUs and consequently in the length of the drying cycle.

 

Please consult the Installation Instructions for the specific Gas Dryer you own for additional installation information.