electric fan relay?

[J. Kennedy]

Hi all. My X is getting an electric fan. I hooked it up to an adjustable thermostat. The instructions for the thermostat say to install a 20 amp fuse in the line, which i did. They do not mention a relay.

Searching posts here, I see people install a relay for fans. Do I need one? What does a relay do? Where in the line should it go?

 

[heyok]

Hi all. My X is getting an electric fan. I hooked it up to an adjustable thermostat. The instructions for the thermostat say to install a 20 amp fuse in the line, which i did. They do not mention a relay.

Searching posts here, I see people install a relay for fans. Do I need one? What does a relay do? Where in the line should it go?

A relay is generally used when the controlling circuit is not able to handle the amount of current drawn by the device being controlled. Based on what you said, the thermostat is supposed to be fused for 20amps which tells me that the thermostat is able to switch up to 20amps of current. As long as the fan doesn't need more that 20amps you are ready to roll without a relay.

Read the specs for your fan and if it needs more than 20amps, you will need to get the thermostat's output to activate a relay that is rated large enough to supply the current needs of the fan.

Another reason to use a relay would be if the thermostat is very expensive to replace. In this case, reducing the load that the thermostat will see by having it turn on and off a relay instead of the fan could save you money as the relay is likely less money to replace than a thermostat.

If this isn't clear enough, let me know and I will try and help some more.

Cheers,
Al