ID window balance

A home owner from Silver Springs, FL says:
Looking to replace this one. 28 1/4 inches long. 9/16 wide, 9/16 deep. B27 stamped on the back. sash is 42W 29H. Double glazed. aluminum (white colored.
User submitted photos of a window balance.
Profile picture of Tom
Tom from SWISCO responded:
Thanks for posting! Before I can recommend an applicable replacement balance, can you first confirm the length of the metal channel? Usually, these channels' lengths end on the inch, not on a fraction. Let me know!
A home owner from Silver Springs, Fl says:
It is still 28 1/4 inches long. I have another defective one from another window width a sash that is 34W and 30H and that one is very close to 28 inches long. maybe the manufacturing tolerances were not very strict. Do you need to know the weight of the sashes?
Profile picture of Tom
Tom from SWISCO responded:
Thank you. In that case, I would recommend the S770-28 channel balance. The next step for you would be to remove your window sash and place it on a scale to get its weight. Then, check the following stamp option strengths to see under which option your sash weight falls.

28B: 12 through 18 pounds
28C: 18 through 23 pounds
28D: 23 through 28 pounds
28E: 28 through 32 pounds
28F: 32 through 36 pounds

Please keep in mind that the weight range information is based on 2 balances per sash. Balances are designed assuming friction in the jamb weather-strip will carry a portion of the sash weight. Suggested sash weights are approximate.
Reply to Thread
Use this form to ask a follow-up question or to share your experience regarding this subject.
(your email address will be kept private and is only used to inform you when a response has been made)