Replacement spring balance

Question

The spring balance string broke.  The window is about 28 lbs 26 3/4 " tall 44" wide.  The metal part of the balance is 24".  The markings in the photo are 23 5 BP Caldwell.  The top piece on the other balance is missing part of the plastic but seems to function fine.  If this balance is properly sized for the window l need an equal replacement.  If it is not properly sized what size should I get?

Casey · Accepted Answer

With this combination of attachments, you could have either the S380-24 or S385-24 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.

The 23 5 stamp on your balances indicates that you would need 2350 spring strength options for your replacement balances but keep in mind that they will be calibrated to support a window sash between 23-27 lbs. If you're sure that the window weighs 28 pounds, we also offer the 2360 strength option to support between 27-30 Ibs. Thank you and let us know if you have any other questions or concerns.

Comparison of the S378, S380 and S385 balance shoes.