Balances (?) to replace on two MI Series 3500 SH windows that will not stay up when raised

Question

These are pictures (from an identical window that is working properly) of the parts I need to fix two MI single hung windows that will not stay up when raised. One is of the top part which I guess acts as a stop, and the other of the bottom part which the window snaps into.  I did not see any coils or coil balances that seem to be pictured when I look up what I need to fix the problem. Perhaps those are for double hung windows. I will need two of each part.  Thank you.

Casey · Accepted Answer

Hello,

We can't be positive with the hardware still installed, but it looks like you have a 15-180 Pivot Shoe and Series 190 Coil Balance springs, sold separately. For the clip cover, see the 15-186.

Alternate image for 15-180

As far as the spring weight, you'll need to locate the stamp code on the original coil springs. Otherwise, you'd need to weigh the window sash these springs support, divided by the number of coils used on both sides. Thank you!