Replacement window balance

Question

I believe the balances I need are 18" Caldwell series. Metal measures 18" long. The stamped numbers/ letters are 17-4 DI5 CMC 34 on the units. I have 3 vinyl windows 4 feet wide and none of them work properly, I'm guessing the balances are not strong enough because they won't stay open. I'm wondering if I should just replace the balances with a 17-5 or ? to help with this situation. See attached photos.

Casey · Accepted Answer

Hello,

With this combination of attachments, you could have either an S380-18 or S385-18 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.

Your stamp code would normally indicate that you need 1740 spring strength options for your replacement balances. Since you said that none of your windows are being properly supported, I would recommend weighing the window sash and following the chart under the balance product description to confirm that you choose the correct strength option for your windows.

Thank you and let us know if you have any other questions or concerns.

Comparison of the S378, S380 and S385 balance shoes.