Coil spring

Hello!

Our 15-087 pivot shoe looks like a match for the part shown in these photos. The Series 180 (sold separately) would be the compatible coil springs. Take a look and let me know if you have any questions regarding these parts. 

With a 19.6-pound sash, you could use (2) S180-5 5-pound coil springs on each side of the window which would total 20 pounds of overall support. You would also need the 15-086 tandem coil housing for this setup. 

Are you saying that you don't think the 15-087 is original to your windows? If that's the case, you may want to check some identical windows in the house to confirm. 

Emily isn't here today, but I will do my best to advise you.

At this stage, it's not possible to judge whether or not your old assembly was meant to install in this window. It's entirely possible that the installers put in the wrong parts, but that's not something I can really determine. is there a reason why you think it's wrong? Is there a particular point of failure that indicates it's not supposed to be on your window?

Right now, based solely on your photos, the hardware Emily recommended is the best replacement for the job. A tandem assembly will fit in the track without issue, though it will be harder to thread into the cutout. It's possible, but I won't lie to you: it won't be easy. It's up to you whether you want to make the cutout larger to accommodate the tandem assembly or not. You don't want to go overboard with it, but a little extra space won't hurt.

We unfortunately don't have a video on this particular balance. 

When I say "threading," I'm simply describing the method by which you put a taller balance assembly in a track cutout. You put the bottom in first and then slide the rest of the assembly in at a kind of angle, effectively "threading" it into a track, much like you'd thread the head of a needle.

The diagram below will show you how these balances are typically assembled in the frame. 

Were you also able to tell me why you don't think your original balances are correct for the window? I'm still not sure what you meant on that point, and it's an important factor right here. If the hardware we're talking about isn't correct in the first place then we need to start looking at other options.

Series 180 coil balance diagram

Gotcha, thanks for explaining. Your analysis seems sound. If the current balance system has worked fine all these years then I see no reason why you can't continue to use the the same style; there is a certain amount of wiggle room when it comes to coil balances, unlike other balance types, so substitutions are fairly common and still totally workable.