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View Full Version : decreased fan motor amperage



icedr024
05-10-2010, 01:55 PM
:worthless:On my air handler, will i get lower than normal amperage readings, if my return air damper shuts or will the motor struggle trying to pull air back causing higher amperage.

mrhvacmechanic
05-10-2010, 06:53 PM
If it's a centrifical fan, the less air you move the lower the amperage.

Octopus
05-10-2010, 07:23 PM
Put your amp meter on motor and remove cover, but yeah most of the time the amps will drop

icedr024
05-12-2010, 07:58 AM
yah thanks for the info

timebuilder
05-16-2010, 08:49 AM
On my air handler, will i get lower than normal amperage readings, if my return air damper shuts or will the motor struggle trying to pull air back causing higher amperage.

When you block off the return air (the damper closes) you are "starving" a typical blower -type fan for air. Less air is available, less work is being done, lower amps will flow to do that lesser amount of work.