Channel Balance replacement
Hello,
It looks like you have either our S351, with a 15-002 bottom attachment, or S390, with a 15-001 bottom attachment. Take a look at the image below to determine which balance you'll need. You'll also need to locate the stamp code on your metal channel to choose the corresponding spring strength option for your replacement balances. Thank you!
If your bottom fitting batches the 1-1/8" deep 15-001, then you would need the S390 channel balance. You'll need to confirm the length of your metal channel, not including the end fittings, in addition to the strength code that I mentioned. From there, you'll be able to choose the correct specifications for your replacement balances on the S390 product page.
Are there any numbers stamped on the metal channel of your original balance? If so, that s what you would use to choose the corresponding strength option.
In that case, you could check the balances of an identical window if there is one in the house. If not, you would need to weigh the window sash on a bathroom scale and follow the chart under the channel balance product description to choose the corresponding strength option.
We're happy to help. Just let us know if you have any other questions.