Looking for replacement coil for Certainteed double-hung window

Question

Hello, I have Certainteed double-hung windows, installed prior to 2004 (unsure when). The bottom sash of one window won't stay up, and when I removed the window I found that the coil spring has snapped on both sides. One picture shows the assembly I removed from the middle of the window on one side. The second picture isn't clear, but it shows the other half of the spring coil which is still in the window above the shoe of the window.

Please help identify replacement parts, and if there are videos on how to replace with new parts that would be very useful.

The bottom half of the coil has a marking "335". Looks like I need https://www.swisco.com/335-Coiled-Balance-Spring/pd/Series-170-Coil-Balance/S170-335

Thank you!

Bob · Accepted Answer

You likely have our 15-192 Certainteed Pivot Shoe, which uses the Series 170 and Series 171 Coil Springs. The video below goes into more detail. A stamp of '335' would indicate indicate you need an S170-335 spring.