Wocd on historic sashes

A handy person from Minnesota says:
January 12, 2020
I have an historic house with period double hung sashes. The city is requiring wocd on the upstairs windows. What is the best device to install?
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Dave Sr. from SWISCO responded:
January 15, 2020

Thanks for writing in. We carry a balance system that wood window manufacturers used in the 1940's, our Series 500. This is a 5/8" tube spiral balance. It is often used with the bottom sash bracket, the 17-012, which attaches to the bottom of the spiral. From the photos, it is hard if these sashes used this method or another. But take a look and see what you think. Also take a look at the other parts associated on this page if you need them.
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