balance inquiry

Question

Have a window with a broken balancer. Sash unit is approximately 25 years old, builder grade double sash where only the lower sash moves..Existing balancer appears to be block and tackle design, but is in pieces...Overall sash unit is 58 inches (inside dimension); movable sash is 29 3/8 in. High, 37 1/2 in wide..
Channel is 5/8 inches by 1/2 inches.
Balancer unit consists of a rod (27.25 inches), surrounded by a spring (12.5 inches loop to loop) and attaches to top of channel with a screw through a nylon bushing that has a shoulder for the spring loop to "capture".
image1.jpeg
There is a cord (37 inches) runs between the top nylon bushing and a lower bushing (3 times) and connects to a "traveler" with a swaged tab.

Lauren · Accepted Answer

Hello, thank you for posting,

From your description, I believe you have an older rod balance that is no longer made. You should be able to convert to the Series 770 channel balance that installs at the top with a screw through the metal channel and uses the same terminal clip that hooks into the pivot shoe.

For an accurate measurement of the length needed, you will need to measure an undamaged version as shown in the diagram below.

Once you have the length, you will need to weigh the window sash and refer to the strength chart on the S770 product page to determine the correct spring strength stamp option to use for the window.

Please review and let me know if you have any questions. If you also need a new pivot shoe, please review the dimensions of the 15-129 to see how it compares to your original.

Detail of 15-129

We recommend replacing both balances at the same time to have the same hardware as pairing a new balance with an old one would cause the new balance to wear out faster.