The Aprilaire #51 current sensing relay simplifies air cleaner installation on furnaces without accessory terminals.  Can also be used to simplify installation of inline duct booster fans.

Voltage Range: 100-125 VAC, 50-60 Hz
Sensing Current: Minimum of 4.0 Amps
Operating Ambient Temperature Range: 40F-104F
Wire Lead Length: 32"
Dimensions: 1" x 1-7/16" x 2-3/4"
Load Ratings: Max (50 Watts) 0.42 amps
Min (3 watts) 0.03 amps

Case Color: Yellow