Coil Balances

Thanks for posting. This looks like our 15-180 Coil Balance Shoe, along with the 15-181 Detent Clip and 15-182 Bushing. This setup uses Series 190 Coil Balances. You have to choose spring weights for the replacement coil springs; these denote the weight each individual spring can support. Stamps on the old springs should indicate the necessary spring weights for replacements; however, it's a bit difficult to make out the stamps on your old springs. They seem to read either 6 or 9--however, you say the window sash weighs 8 pounds, and so that would seem too strong for your window in either case. Please double-check the exact sash weight, and we can work out the exact spring weights you need. 

Sure, so with an 11.5 pound sash then you can actually downgrade to only using one spring per side, instead of two. I would specifically recommend our S190-640. These carry 6 pounds each, so having on on each side will give you 12 pounds of support. That should be perfectly sufficient for a 11.5 pound sash.

That also means that the 15-181 double support is no good. You would instead want the 15-186 single spring support.

The round bushing goes over the pegs in the support. The pegs are a little too narrow by themselves and without the bushing, the spring is likely to rattle around during use.

As for why you want the smaller detent clip, it's because you're going down to one spring per side instead of the two you originally used. I went over this in my response to you back on the 19th of September: for an 11.5 pound sash, you can use just one 6 pound spring per side. 

No, the peg I'm talking about is on the detent clip, not the pivot shoe. If you look at the back side of your current clip, you'll see two pegs sticking straight out. The coil fits over these pegs when the whole assembly is put together. 

If you just put the spring on the detent clip as-is, it's going to shift during operation since the peg isn't big enough to fill the inner diameter of the spring. The bushing prevents that from happening.

As for using a single detent versus a double detent, it's ultimately up to you. If you have a double detent that only used a single spring, then that means that someone installed the wrong part in your window. I personally find the single detents easier to install, but it is up to you at the end of the day which one you go with.