Coil Balance

Question

I need to replace my window coil. The window is 21 lbs. The coil housing has the number 7 written on it and the coil currently installed is 1/2" wide. Which coil balance would I need to purchase in order to fix my window?

Bob · Accepted Answer

Hello there. This looks like a 15-087 Pivot Shoe and 15-086 Tandem Housing. This system uses Series 180 Coil Balances. All these parts are sold separately. Please confirm that the window sash weighs exactly 21 pounds. If so, you really could just use one coil on each side, the S180-10 10 pound spring. In this case you'd need just the 15-087 and not the extra housing. A 10 pound spring on each side would equal 20 pounds of support overall--being within 1 pound of the exact sash weight works fine. If however the window weighs even just slightly more than 21 pounds, go with the S180-05 5 pound spring and S180-06 6 pound spring. Use a pair of these on each side of the sash, for a total support of 22 pounds. Let me know if you have further questions.

Series 180 coil balance diagram