MI Window Coil Balance Spring

Question

Looking for want replacement part I need to buy for a MI window coil spring. On one side of the window, the spring broke and the window will not stay open. Picture is of the coil balance on the working side of the window. I would be fine buying just the metal coil itself, but do not know how to determine the size?

Casey · Accepted Answer

I see you have a Coil Balance Shoe, 15-180 and a Coil Balance Clip, 15-186. These are usually used with the Series 190 Coil balance. Look for a number printed on the metal coil that indicates the number of pounds it can carry. If you can't find that, you'll want to weigh your sash and divide that weight by the number of coils that support it. Each coil will carry that number of pounds. For example; if you have a 10 pound sash and two coil balances supporting it, each coil balance will be 5 lb.