Springs are separating from sash

Question

I have 1/2inch wide, 30 inch long springs for single hung, non-tilt windows. For some reason the springs have been breaking though the sash cap. I'd like help finding the right spring and sash caps, and some ideas about why that would happen in the first place. There is no stamping on the springs but on one I can barely make out JW CMC 11.

Thank you!

Emily · Accepted Answer

Hi there!

With this combination of attachments, you could have either an S380-30 or S385-30 channel balance. You’ll need to measure as shown below. The Series 380 has a 1" bottom attachment, and the Series 385 has a 1-3/32" attachment. If there is no stamp on your metal channel, you'll need to weigh your sash and choose a spring strength option on the chart under the product description on our website.

There could be a few reasons as to why your balances are breaking through your top sash guides. Either your balances have too strong of a spring strength or your top sash guides need to be replaced.

Comparison of the S380 and S385 balance shoes.