Window balance replacement and upgrade

Question

The attached pic is for a broken 20 year old window balance. It measures 1 3/16" wide and has 8 stamped on the coil.
HOWEVER the window glass was recently replaced; the entire frame plus glass now weighs 25 pounds.
I suspect I need two S140-13 replacement parts, would appreciate it if you could confirm or suggest otherwise.

Bob · Accepted Answer

Hello there. This is not the Series 140 assembly. It is actually a 15-180 Pivot Shoe, which works with Series 190 Coil Balance springs sold separately. If the window weighs 25 pounds exactly, then in theory you could use the S190-940 9 pound spring and S190-440 4 pound spring, a pair for each side of the sash. That would give you 13 pounds of support on either side of the window, for a total of 26 pounds overall--being within 1 pound of the actual sash weight works just fine. Just make sure that the sash does weigh 25 pounds. Also bear in mind that since the window has been modified from what the balance system was originally intended for, there is a chance that this might not work. That said if you're confident in the sash weight I think you'll be okay.

For covers for the springs, see the 15-182 and 15-181 drums.