Casey from SWISCO responded:
April 8, 2011
Hello,
If pivot shoe is in working order, there is no need to replace. 28" Series 770 with 27D stamp will carry a window sash weight range of 23 through 28 pounds. This will work well for a 25 pound sash. 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. |