Certainteed somerton II windows

Thanks for posting. This looks like a 15-192 Pivot Shoe. This is compatible with our Series 170 and Series 171 Coil Springs. The Series 171 has a longer tongue and is meant to stack 'on top' of the Series 170. The '10' stamp on your old coil could indicate the spring weight, yes, but I am afraid we don't carry any Series 170 or Series 171 with that spring weight. What I would do is weigh your window sash. Then divide that exact weight in half to know how much spring weight support you need on each side of the sash. For example, let's say your sash weighs 20 lbs. Dividing that in half would get you 10 lbs of support needed on either side of the sash. What you then could do is use a S170-405 and S171-405 on both sides of the sash. Each of these coil springs are for 5 lbs of support individually, totaling the 10 lb of support needed on both sides of the sash. Just weigh your window sash to confirm the needed weight, then go from there. Let us know if you need help. 

I'm afraid we don't carry any 10 lb springs for the Series 170. Stacking another coil spring atop the other and attaching both to the Pivot Shoe really isn't any issue; you just use the 15-156 Lance Spring Cover and Series 15-157 Balance Drum to keep each spring secure. We quite frequently have customers who end up with either fewer or more coil springs than they did before; all that really matters is matching the weight support needed. In your case, going with two 9 lb springs would leave you 2 lbs short of 20 lbs; that's a bit too much margin of error in my opinion. I recommend going with (4) of the S170-405, which supports 5 lbs each. Stacking two on each side of the sash would equal the 20 lbs of spring weight support needed. 

My pleasure. Thanks for considering our business, we really appreciate. If you have any other questions do not hesitate to ask.

Awesome! Thanks for letting us know how you made out, it's great to hear your window is in working order again. If you need anything else from us, again, do not hesitate to ask.