If you know what you are doing, it is very simple to adjust the speed of your furnace fan. There are only a few steps required for most units and having the control will allow you to get your unit to give you the service you need.
Find and Remove the Cover
Before you begin this process it is a good idea to make sure that no power is going to the fan. This will help prevent injury and damage to the furnace fan.
You will need to find the main cover panel on your fan. If you are having problems, find your fan’s user’s manual and use it as a guide. Once you have located the panel, remove it. This will allow you to access the control board.
Switch the Jumper
On most control boards there will be a jumper that is marked to show that it controls the speed. Most of these are on the bottom left of the control board. Then switch the jumper to your desired speed. Usually there will be three “speeds” ranging from 40 to 100% of airflow.
To switch the jumper, you will need to hold onto it gently as you pull it out of its current setting. Then, carefully switch it to the setting of your choice and push it back into the control board.