S770 Option - which one?

A home owner from Monument, CO says:
August 16, 2010
My channel balance has 27TGX stamped on it but is 28" long. Not sure which option to order (28d, 28c or 28b)? It is from a double pane double hung window 42" wide by 60" tall (sliding part of window is 42" wide by 29" tall).
A home owner from Monument, CO says:
August 17, 2010
Following up on my customer questions and comments. I have a balance that needs replaced. It has 27TGX stamped on the channel but is 28" long. I don't know which one to order. It is on a 42" wide by 29" tall window (these dimensions are of the window that moves). See pics.
Thanks,
Eric
Customer image of their S770 channel balance.
Profile picture of Donna
Donna from SWISCO responded:
August 17, 2010
Please remove the window sash and place it on a scale.
We need the weight of the window sash in pounds to determine the proper stamp option.
A quick learner from Monument, CO says:
August 17, 2010
The window sash is 25 lbs.
Profile picture of Donna
Donna from SWISCO responded:
August 18, 2010
S770-28 balance with stamp option 28D will carry a window sash weight range of 23 through 28 pounds.

This 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.
A quick learner from Monument, CO says:
August 19, 2010
What are the sash weight ranges for the 28B and 28C options? I have other windows that will need new balances in the near future.
Profile picture of Donna
Donna from SWISCO responded:
August 19, 2010
S770-28 with stamp option 28B will carry a window sash weight range of 12 through 18 pounds;
S770-28 with stamp option 28C will carry a window sash weight range of 18 through 23 pounds.

This 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)
Current wait time is 4-7 business days
We promise that one of our experts will personally get back to you as soon as they are able. Thank you very much for your patience and understanding. If your inquiry is time-sensitive, please feel free to reach us at 856-317-6263 or at help@swisco.com.