MI 3500 - Replacement Sash Support Coil Balance

Thanks for posting. I'm afraid I can't narrow down what you need from this information alone, as this hardware varies a bit from window to window. Can you show me a picture of the pivot shoe that the coil balances attach to? The identity of the pivot shoe tends to determine the identity of the coil balances needed. 

This looks like the 15-181 Double Support Detent Clip, which works with the 15-180 Pivot Shoe. This system uses our Series 190 Coil Springs. To know what spring weights you need, look for stamp numbers on the coil tape. If there are none, or you are uncertain, obtain the exact weight of your window sash. Give us that exact weight, and we'll work out what you need.

If the window weighs exactly 22 lbs, then you'd need a S190-540 5 lb spring and S190-640 6 lb spring on both sides of the sash. This would equal 11 lbs of support on both sides of the window sash, for a total of 22 lbs of support. Let me know if you have any other questions.