Window balancer coil spring replacement
Thanks for posting. The coil carrier looks like the 15-252, which works with Series 160 Coil Balance springs sold separately. If the coil carrier is undamaged I don't see any reason why you can't reuse it. That '12' on the carrier might indicate the coil springs on either side of the sash can carry 12 pounds of support, which means that they'd support 24 pounds overall--but I advise you weigh the window sash just to confirm that makes sense. See the video below. Assuming these numbers are accurate, use the S160-05 5.5 pound spring and S160-06 6.5 pound spring, a pair for each side of the sash. That would equal 12 pounds of support on both sides, for 24 pounds overall.
Two additional follow-ups questions:
1 - Is there a preferred installation method for the coils - does the 5.5 pd go on the top or bottom of the coil carrier? Since there are two different weights, not sure which to put on top or bottom. My guess is it doesn't matter but figured I'd ask.
2 - Why wouldn't two equal 6 pd coils be used to get to 12 pds (as opposed to one 5.5 and one 6.5). Just curious. Wondering if its related to what is available/typically manufactured.
Thank you again!
Good questions. In our experience it doesn't really matter which coil spring you put on top or bottom of a double assembly. They are traveling the same distance and will pick up their respective weights. As far as why you can't just choose (2) six pound springs, it's just a weird thing about how this particular system works. The Series 160 Coil spring weights all come in X-1/2 pound increments (at least until you get to ten pounds or more). It makes adding up the spring weights a bit more confusing than those systems that just have even weights, but as you can see it still works out okay. Let us know if you have further questions!