Balance Spring for CertainTeed double hung window

Thanks for writing in. I'm fairly confident we can replace this balance system for you, but I want to be safe and confirm we know what components we're working with. Can you show us pictures of the pivot shoes that the coil balances attach to? The identity of the pivot shoe determines the Series of coil balance needed. From there, we'll work out what you need for each window. Many thanks.

Thanks for getting back to me; perfect, this is exactly what I needed. Your pivot shoe looks like our 15-192. This is compatible with our Series 170 and Series 171 Coil Balances. If you need just one coil spring on each side of the sash, then you'll only need the Series 170. Specifically, your stamp code suggests you need the S170-336, which is meant to hold 6 lbs of weight individually. Let me know if you have any other questions.

In that case, you're going to have to divide the weight between multiple different springs. Specifically, you'll need two on each side.

I recommend using our S170-406 (6 pounds) and S171-405 (5 pounds) on each side of the sash. These four springs should add up to 22 pounds of support. You want to install the S170-406 on the bottom and the S171-405 on top. You'll also need a second 15-156 cover for support, as well as another 15-157 bushing.

Being within 1 pound of the actual sash weight works fine. So, if the window indeed weighs 23 pounds, using the S170-406 6 pound spring and S171-406 6 pound spring on both sides of the sash equals 24 pounds and should operate well. Similarly, for a sash that weighs exactly 19 pounds, a pair of S170-405 and S171-405 on each side, to equal 20 pounds overall, should work.