#170 coil balance

A contractor from Bellflower, CA says:
January 4, 2022
Hello,

I have a customer with a Certainteed double hung window with what appears to be a #170 coil balance. However, the only stamp on the balance that I can locate is 10 J. Can you make any sense of this?

Thanks for your help,
Profile picture of Bob
Bob from SWISCO responded:
January 6, 2022

I am afraid a 10 pound version of the Certainteed springs is not available. There's a solution however. If this is a Certainteed Coil Balance system, and the single spring is stamped with a 10, then what we recommend is using a S170-405 5 pound spring and S171-405 5 pound spring in tandem on each side of the window. This will equal 10 pounds of support per side, for 20 pounds of support overall. The video below explains how these parts work together. 
405 Series 170 Coiled Balance Spring
405 Series 170 Coiled Balance Spring
S170-405
$6.52
405 Series 171 Coiled Balance Spring, Long
405 Series 171 Coiled Balance Spring, Long
S171-405
$6.55
CertainTeed Pivot Shoe
CertainTeed Pivot Shoe
15-192
$6.39
SWISCO S170 and S171 Coil Balance Assembly
SWISCO S170 and S171 Coil Balance Assembly
VIDEO
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How to Replace a Triple Coil Balance System
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How to remove window pivot shoes
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Removing a Triple Coil Window Balance
Removing a Triple Coil Window Balance
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