coil spring system replacement
Thanks for writing in. I can't be certain without seeing the shoe out of the window, but I believe you might have our 15-228. You'll have to remove the pivot shoe and compare to confirm. The identity of the pivot shoe determines the identity of the coil springs used.
Our 15-228 uses either our Series 160 1/2" wide springs, or our Series 165 3/8" wide springs. You'll have to remove your existing coil spring from the window and compare its width to see which Series you need. Look for a stamp code on the spring tape that indicates what spring weight you need. If there is none, or you are uncertain, give us the exact weight of your window sash, and we'll work out what you need.
If the housing and shoe are undamaged, there is no need to replace them. The housing is our 15-150S.
For information on how to remove and replace your coil balance system, see the video below.
Does it take special equipment to install the spring into the shoe?
Thank you! Since your spring is 1/2" thick and stamped with "7.5," I think our S160-7 is what you want. This is fully compatible with your 15-228 shoe. That "T" shaped tab at the end of the spring just snaps into the shoe, no special tools necessary. You can do it by hand.
Please let us know if you had any questions!