window balance stamped 28A and 28B

Question

Good morning,
I have to replace 56 window balance for a customer.
I could find stamp on every balance 28A and 28B, I am about to order the
S380-29
29" Series 380 Channel Balance, do you think it's correct?

The window that cause me issues is one where there is no stamp, its a 51.5"x31" single hung, in your experience what could be the stamp I have to look for? They are recent vinyl windows.

thank you for your help

Casey · Accepted Answer

Hello,

With this combination of attachments, you could have either an S380-29 or S385-29 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. You'll also need 2810 spring strength options for your 28A balances and 2820 for the 28B balances. Keep in mind that both balances form each window should have the same stamp code.

If one of the windows has no stamp on the balances, you'll need to weigh your sash to determine which strength option you'll need. There is a chart on the balance product page that explains how to choose your option based on the sash weight. Thank you and let us know if you have any other questions or concerns.

Comparison of the S378, S380 and S385 balance shoes.