window weight

A quick learner from san francisco says:
I have two size windows 46 x 57 and 22 x 57 they both have 27 4 KO Caldwell channel balances this does not seem correct to me. Is there a formula for this? The windows are dual pane.I do not have access to weight the windows now that I am in a different city.
User submitted photo of their 27 4 KO Caldwell channel balance.
Profile picture of Donna
Donna from SWISCO responded:
I cannot confirm the balance series by the one photo. I need to see photos of both the top and bottom plastic attachments.

A S380-28 with stamp option 2740 (this should replace the 27 4), will carry a window sash weight range of 19 through and including 26 pounds. To check the sash weight, remove the window sash and place it on a scale.
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