Channel balance

Question

I have several vertical sliding windows from the 1990s. They are double-pane glass windows, with a screen either between the panes or, in some cases, on the exterior side.
The window balance on the lower side is broken, so I can no longer push the window up and have it stay in place. On most of the windows, a small component of the balance has failed. The main problem is that the internal pulley is broken.
The balance is marked only with “31C.”
Its length is 84cm(33inch), and the metal channel width is 1.5cm(0.6inch). Can you please check the photos i provided?

Jasmine · Accepted Answer

Thanks for your post! This balance is a match for either the S351-32 or the S390-32. The length of the channel should be 32", only the metal. To determine the correct series for your repair, you'll need to confirm the depth of your bottom shoe.

Our 3130 stamp may work in place of your 31C stamp, but you may want to double check that your sash weighs between 16 to 23lbs.

Comparison of the S351 and S390 balance shoes.