Coil balance

Question

Sash weighs between 14-15 lbs. There is a patent number 5,353,548.  One side is marked 3 or B with a marker.

Casey · Accepted Answer

Your pivot shoe resembles our 15-087 that is used with the Series 180 coil springs. Based on your sash weight, you would use one S180-7 coil spring on each side. Take a look and compare the specifications to your hardware and see what you think. Thank you.