Single coil balance and pivot bar replacement

Thanks for posting. Looks like you have a 15-175 pivot shoe, which is compatible with our Series 152 coil spring. You'll need the stamp printed on the old spring to confirm the best Series 152 option. You should be able to reuse your old covers.

As for the pivot bar, it might be our 26-226. You should review our dimensions to be sure, especially the distance between the center of the first hole and the tip that goes into the pivot shoe.

Thank you for replying back with more information. Since your coil spring does not have a stamping or marking on it, the only way for us to recommend the proper strength coil, would be to have you get back to us with the exact weight of your sash. This is the only way we can determine which coil spring to suggest. 

Thank you for providing us with the sash weight. You will need two coil springs on each side of the window: a S152-9 and a S152-4. Those two coils together will hold up a 13 pound sash weight. So, with that set up on each side of the window , it will hold a 26 pound sash weight. 

Thanks for double checking that sash weight. If the sash is only 18 pounds then a single S152-9 on each side ought to do it. Using the same math that Manuela went over, two 9 pound springs will hold up an 18 pound sash.