Spring coul
Thanks for reaching out! The top window is likely falling because the coil spring, the pivot shoe, the pivot bar, or the entire assembly is damaged in some way. To identify the correct replacement for your existing coil balance assembly, I'll need to see a photo of the pivot shoe removed from the window. It would also help to see the pivot bar.
You'll also need to remove the coil from the window to confirm any stamps/markings on the metal. This number will give us the spring strength needed for the coils in the window. If there are no stamps/markings, I'll need to know the exact weight of the sash.
Please let me know if you have any questions.
I'm sorry to say that I cannot identify the replacements you need base on these photos. The sticker does not indicate the hardware used in the window as oftentimes the manufacturer of the window is not the same as the manufacturer of the hardware.
I'll need to see the coil balance pivot shoe which is connected to the bottom of the sash. You'll need to remove the sash from the window completely to be able to see the shoe and remove it. Please take a look at the videos tagged below for reference.
To determine the spring strength you need for the coils, you'll need to obtain the exact weight of each sash you are looking to replace the assemblies in.
Please let me know if you have any questions.
Thanks
Your coil balance shoe reminds me of the 15-192 CertainTeed Pivot Shoe. To confirm that this is the correct replacement, carefully review and compare the dimensions below. Keep in mind, you may need to shave down the aligners so the shoe will fit in the window channel.
The shoe is compatible with the Series 170 Coil Balance. Since yours is stamped with a 406J, you'll need the S170-406.
To replace the balance cover, you'll need either the 15-156 CertainTeed Lance Spring Cover, Wide or the 15-185 CertainTeed Lance Spring Cover, Narrow.
