Window balance spring

Question

Good morning. I am looking to order the correct balance springs for my windows. The springs are 1/2" wide and 29" long on the metal part of the spring. If you could help me identify the correct spring I need to order around 14 to 16 of these items.

Thanks, Ryan

Jasmine · Accepted Answer

Thanks for writing in! It looks like you have either the S351-29 with a 1" shoe or the S390-29 with a 1-1/8" shoe. To determine which series is needed for your window, look over the dimensions from the diagram below to confirm the depth of your bottom shoe. You'll need to select the 2830 stamp for a window weighing 16 to 23lbs.

Comparison of the S351 and S390 balance shoes.