One window won't stay open

Question

It's the left side of these double hung tilting windows that we believe were from Stock Building supplies and installed by builder into our new house in 2005.
Just not sure what parts needed, they look like coil broke.
Any help? Or any more info I can provide you?
Thank you so much for even having this website.
Jihn

Bob · Accepted Answer

Thanks for posting. If the window won't stay up, chances are the coil balances are broken. Those are the spring mechanisms in the window tracks; they're tensioned and regulate the window's movement. Judging from your windows I suspect yours have snapped or are at least worn down. From what I can see, I believe you have a 15-180 Pivot Shoe that connects the window sash to the coils. The 15-180 works with Series 190 Coil Balances. Now, each coil spring has a spring weight, which basically denotes how much weight it alone can support. There should be stamps on your old coils that indicate the spring weights you need to pick for each replacement; but if there are none or you're unsure, just weigh the window sash the coils support. Give me that exact weight and I can work out what you need.

It's best to replace all the coil springs in the window at once to ensure smooth operation going forward. The video below shows how to remove and replace a similar coil balance system. Check it out to learn the installation process.