CoiL Spring

Thanks for posting. This does look like the 15-102 Double Carrier to me. This works with Series 145 Coil balance springs, and the S145-4 4 pound spring and S145-7 7 pound spring should be what you need, respectively. Let me know if you have further questions.

Unfortunately, we don't have a video to show how to install this specific setup, but I will try to summarize the installation process as clearly as I can.

These coil springs install differently than other assemblies in that the coil attaches directly to the jamb itself. This presents a unique type of installation.

1. You'll note slots in the jamb where the balance installs; your first step is to rotate the springs into those slots, making sure that the end tabs are facing up.

2. Next, snap the 15-102 spring carrier over the springs. Take care that the lowest pocket is used first. Then use both hands to apply downward pressure to hold the carrier firmly against the jamb, carefully extending both the carrier and springs downward together. (Note that the springs are loaded under tension, so this will require some elbow grease. Make sure to keep a firm grip on the carrier so that it doesn't slip away from you; if it does, it will shoot back up the track.)

3. When the balance is in alignment with the lock slot in the jamb, press the sash lock completely into the lock slot. It is imperative that the lock be flush with the carrier to ensure full engagement.

4. You can repeat these steps for the opposite side.

5. Once both sides are installed, load the sash above the carrier assemblies and center it between the jambs. Ease the sash down into a resting position on the carriers, then apply slight downward pressure to the sash to unlock them. They will now be free to operate as normal.