Broken Balance

Thanks for writing in. This shoe resembles the Certainteed 15-192, which uses Series 170 and Series 171 Coil Balances. See the video below for details. 

There is an important catch with this: note that if your window is not from Certainteed, that we've found the 15-192 often doesn't fit correctly, not without rubbing down the alignment nubs on its face. Even then it's no sure thing it will work in a non-Certainteed window. Because of this issue, we've devised an alternative solution: the 15-259 Pivot Shoe, along with Series 159 Coil Balances, should work in your jamb track. The video below explains how to make this conversion. Let me know what route you choose to take, and if you have any further questions. 

If there are no markings on your original spring, then your only other option is to weigh the sash on a scale and then divide that weight by how many springs support it. In your case, that'd be 4 (2 on each side).

So, for example, if your sash weighs 20 lbs., then you'd want a 5 lb. option for each spring. If all four springs carry 5 lbs., then they'll support 20 lbs. perfectly fine all together. Does that make sense?

Here's where it gets a little tricky. The Series 159 that is used with that 15-259 pivot shoe are weighted in half pound increments. 3.5 lbs., 4.5 lbs., etc. That means that dividing your sash weight evenly between your springs probably won't get you an exact match. In the example above, you would instead use a 4.5 lb. spring and a 5.5 lb. spring on each side, which adds up to the same total support. As long as the assemblies are symmetrical on each side of the window then you should be okay.

Hopefully that makes sense. Please let me know if I can be of any help and I'd be happy to assist. If you want, you can just give me your sash weight and I'll give you my recommendation for weight combination.