800 series 29 " 28 F Balance

Hello,

The S800 balance has a thinner 3/8" wide channel than most of our replacement balances, which measure 1/2" wide. To my eye, it looks like you have a standard 1/2" channel. If so, you could have either our S351-29, with a 15-002 bottom attachment, or S390-29, with a 15-001 bottom attachment. Take a look at the image below to determine which balance you'll need. 

Based on your 28F stamp, I would generally recommend 2860 spring strength options for your replacement balances but they would only support a sash between 32-35 lbs. If your sash weighs exactly 43 pounds, we should still be able to supply replacements through a custom order. We'd just need to confirm the depth of your shoe and the number of balances you need, with the minimum being two. Thank you!

Comparison of the S351 and S390 balance shoes.

If your bottom fitting measures 1" deep, you would need the S351-29 channel balances. The S351 and S390 are the same balance except for the bottom fitting, which is why we base our recommendation on the shoe depth. We'll work on getting an order link and price quote together for you. 

Good news! We were able to add 2875 strength options to the S351-29 product page, which will support a sash between 42-45 lbs. Take a look and let us know if you need anything else.