Window coil balance, spring coil replace? Help

Hello! Your spring isn't made anymore, unfortunately. The good news is, you should be able to use our Series 152 as a substitute. Your pivot shoe would be a match for our 15-177. These two products are explicitly designed to work together, so I feel pretty confident this is the setup you want.

If you only have one spring on each side of the sash, you could either go for two 8 pound springs (S152-8) for 16 pounds of support, which is a little under, or two 9 pound springs (S152-9) for 18 pounds of support, which is a little over. It's up to you which you want to go with.