Need a constant balance spring identified. For Milgard, 2021, double hung window.

Question

Both springs, on each side of the inside window (double hung), for the constant constant force balancers broke in quick succession (I heard one of them snap). There are no part identifications that I can see on the springs/coils and the only markings on any other parts appear to be patent I.D.'s.

I've upload two pictures of one of the balancers w/spring. It seems that I should be able to easily replace the springs if I can find the right size and strength.

Thanks in advance for any help.

Jasmine · Accepted Answer

Thanks for posting! Your coil balance shoe reminds me of the 15-191 Heavy Duty Pivot Shoe. I am confident this is the replacement you'll need but be sure to double check the dimensions below.

Alternate image for 15-191

This shoe is compatible with the Series 160 Coil Balance which would be used along with the 15-150S Coil Single Support for your assembly. To determine which springs you need, you'll have to look for any stamps/markings on the metal. If there are none, you'll need to obtain the exact weight of the sash and divide that number by the total number of coils in the window.