Searching for Tension springs 3540 sh (fin)

Question

In need of 2 tension blocks. In picture the top portion is cracked. Want to replace both sides. The window series 3540 sh (fin). R-pg40-1118x1600 (44x63)- H
SERIES 3540SH(FIN)

Jasmine · Accepted Answer

Thanks for writing in! Your coil balance assembly appears to be the Series 161 Roller-Tilt assembly used along with the 15-086 Tandem Coil Housing. To confirm that these are the correct replacements, carefully review and compare the dimensions below.

Alternate image for S161-08

Detail of 15-086

The tandem housing is compatible with the Series 180 Coil Balance. Although, I am not sure if your tandem housing is stamped with a 6 or a 9. With that said, you'll need to obtain the exact weight of the sash to confirm the correct spring strength. If the sash weighs 28lbs you'll need the S180-6 but if it weighs 34lbs you'll need the S180-9.

Since the Roller-Tilt assembly is stamped with an 8, you'll need the S161-08.

Please let me know if you have any questions.