Window Balance Identification or Problem

Question

I have two windows that need new balances as the balances slip up past the top of the slider when closed and the pulley systems are deteriorating. The markings on them are 2640 XF BSI, and 2620 NL BSI.

Bob · Accepted Answer

Thanks for posting. Confirm that the length of the metal channel in both sets of balances is 27", not including the nylon attachments at either end. If so, see our S380-27 or S385-27. The only difference between these two balances is the 'depth' of the bottom nylon shoe. Compare both with your old balance to see what matches best. You will need to select stamp options of 2640 for one set, and 2620 for the other set.

I'd like to mention one other thing. You mention that your balances 'slip up past the top of the slider'. Do you mean the balances are shooting past your window sash (as it appears they have in at least one of your photos)? If so, then you may need to replace your Top Sash Guides. The Top Sash Guides are nylon pieces in the top corners of the window sash that keep the channel balances in place during window operation. Now, if the pulley system in your channel balances is deteriorating it certainly warrants replacing them, but if your Top Sash Guides are damaged we can replace these for you as well. We just need to see pictures of the 'front' and 'side' of one of the guides, preferably an undamaged version and out of the window. Many thanks.