Bob from SWISCO responded:
August 25, 2020
This looks like a 15-191 Pivot Shoe, which uses Series 160 1/2" thick Coil Balances. For a sash that weighs 19 lbs, I'd use (2) of the S160-4 4.5 lb springs on both sides of the sash. This equals 9 lbs of support on either side of the sash, for a total of 18 lbs of support overall--so long as the window sash weighs exactly 19 lbs, being within 1 lb should work fine. For new supports, see the 15-150D. |