29-4 BA CMC 11

Hello,

We'd be happy to help but we would need to see a photo of the connecting point between the spring and pulley system to confirm the type of balance that you need. Please also write out the exact depth of the bottom fitting shown in your first two photos. Thank you! 

Thanks for getting back to us but, unfortunately, your new photos do not show the connecting point between the spring and pulley, which is at the center of the balance. 

Great, this is exactly what we needed to see. With this combination of attachments, you could have either the 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. 

You'll also need 2940 spring strength options for your replacement balances. Thank you and let us know if you have any other questions or concerns.

Comparison of the S380 and S385 balance shoes.

If the balances are not staying in place below the sash, you may have a broken top sash guide. Take a look at the video below to confirm if that may be the case. If so, we'd need to see photos of an intact guide removed from one of your windows to compare to our inventory. Thank you! 

To my eye, the top balance fitting shown in your new photos appears to be the same as the one shown in your previous posts. If they are the same balances but different lengths, it would make sense for both windows to use the same top sash guides. 

I'd recommend starting by removing your guide from the sash frame to compare to the specifications of the 18-166 shown below. 

Detail of 18-166

Profile view of 18-166