SWISCO - The Replacement Hardware Authority

Coil Balance installation

A home owner from San Jose says:
I have a 35 lb window double hung tilt sash window that will not stay open. Each side of the window uses three series 180 coils, one 15-087 and two 15-086 tandem housings (coils appear to be marked 6 lb / 6 lb / 7 lb - so it should provide a total balance weight for ~ 38 lbs).

The lower sash raises to open. The sash is not staying open because one or more of the coil springs on each side has slipped off of the 16-024 mounting bracket. The top coil is accessible, but the middle and bottom coils are not - they have "retracted" to their fully coiled positions. There is a cutout at the top of the track, and this cutout is large enough to take each of the housings individually (not together). I.e. first one has to load in the 15-087, then slide it down so that it is most of the way clear of the cutout to before sliding in and mating the first 15-087 tandem / coil, and repeating for the second tandem / coil.

I can clearly see how all of this assembles together. What I can't figure out is how to get all 3 coils mounted onto the 16-024 at the same time.

Once the full 3-stack (15-087 + 15-086+15-067 plus coils) is assembled into the track, I only have physical access to the top coil - the middle and bottom coils have "retracted" to their fully coiled positions. Mounting the top coil is straightforward, but clearly insufficient to bear the weight of sash - the middle and bottom coils are needed for that.

I am clearly missing something - any help is greatly appreciated!
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Paul from SWISCO responded:
I see what you mean. It's difficult to install two coils in this kind of window, let alone three. The manufacturer has actually come out with a more simple coil spring set up. Check it out and let me know if you think you could get this to work in your window. It is our S140-18. This is meant for use with a 35 pound sash. You would also have to replace the pivot bar with our 26-405.
A quick learner from San Jose says:
Thanks Paul! I considered those, but the 15-087 is 1.25" x 0.5" where the S140-18 is actually 1.25" x 0.54" (about 1/16" wider) - do you think the S140-18 will fit appropriately in the track? If so, I agree that looks to be the best solution. Thanks!!!!!!
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Paul from SWISCO responded:
Hmm... I think S140-18 will still fit, yes.
A quick learner from San Jose says:
Thanks Paul - just received the S140-18 units. Installation was straightforward and fast. That design is a significant upgrade from the 15-087 units - thanks for the advice!
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Paul from SWISCO responded:
It was my pleasure! Glad everything worked out. If you need anything else, you know where to find me.
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