Need assistance identifying correct coil balance please

Quick Learner from New Jersey

Dec 20, 2025 3:01 pm

Hello,
Can you please help me identify the correct replacement for what looks like a tanden balance (shown in photo). The broken coils are marked "4FC" and "5FC" (shown in photo). The coils are 15/32" wide. Can I replace this with one Series 161 9 lb single spring on each side, or do I need to replace the 4 lb and 5 lb springs with new Series 181 coils in tandem on both sides.
Also, can you please tell me how I remove the old tandem cartridges? I don't see any screws.
Thank you!

3 user uploaded images

10 Replies

Bob from SWISCO

Dec 21, 2025 1:06 pm

Hello there. This looks a 15-087 Pivot Shoe and 15-086 Tandem Housing. This setup works with Series 180 Coil balance springs. For a spring stamped '4', use the S180-04 4 pound spring; for a '5' stamp, use the S180-05 5 pounder. For a new mounting bracket, see the 16-024. To remove and replace this kind of system, see the video below. It shows a slightly different setup, but the general principles should apply.

Series 180 coil balance diagram

Quick Learner from New Jersey

Dec 21, 2025 5:31 pm

Thank you Bob,
The instructional video says that I can ony use this installation method on the bottom/inside sash, but I need to replace the coils on the top sash. Can I use the same install method on the top sash? Also, do I really need to cut the window track? I have seen where a blow dryer is used to soften the track to open it and remove the cartridge. Any inea if that would work? Or not advisable?
Thank you again,
Dean

Bob from SWISCO

Dec 22, 2025 12:49 am

Hey Dean. For an upper sash, you can form the cutout, but you want to form the cutout towards the bottom of the track instead of the top. As far as alternatives to forming a cutout, yes, you could use the blow dryer method, but this does come with risk--if the window track doesn't cool down evenly, you could cause the track to be bent awkwardly and this could compromise window movement. You also could use jamb spreaders like the 75-069, but the cutout method is the most cost-effective solution.

Quick Learner from New Jersey

Dec 22, 2025 10:47 am

Thank you!

Bob from SWISCO

Dec 22, 2025 3:24 pm

My pleasure. Let us know if you have further questions, and happy holidays.

Quick Learner from New Jersey

Dec 31, 2025 8:54 pm

Hi Bob,
I hope you enjoyed your holidays.
One more question for you on the thread above before I order: Will the pivot shoe fit both the left and right side of the window frame? I see that there are no L and R requirements.
Thank you!
Dean

Bob from SWISCO

Jan 2, 2026 3:27 pm

Hey Dean. Happy new year to you and yours. Yes, the 15-087 and all these associated parts are nonhanded, and will work for either side of the window. Let us know if you have further questions!

Quick Learner from New Jersey

Jan 2, 2026 7:52 pm

Thank you Bob!

Bob from SWISCO

Jan 3, 2026 9:10 pm

My pleasure. Let us know if you have further questions!