Channel balance identification and replacement

Question

Hi, I need to change the channel balances on two windows (see attached photos). I have narrowed it down to models 351 and 390, but I can't tell the difference between the two. The length is 27 inches. The current balances are labeled 2630 and 2620 (right and left side). Can you help me understand which model I need? Thank you very much.
Stefano

Jasmine · Accepted Answer

Hi Stefano,

You'll need to measurement the depth of the bottom shoe to determine the correct series for your replacement. It should be either 1" or 1-1/8", front to back, as shown below.

Comparison of the S351 and S390 balance shoes.

In regard to the stamps, there should be two differing options in the window. This means the weight is being unevenly distributed, which can cause damaged to the window track or cause the balances to malfunction. It is likely the reason you're needing to replace them now.

To determine which option is correct, you'll need to confirm the exact weight of the window sash. The 2630 will support 13 to 19lbs and the 2640 will support 19 to 26lbs.