Concerning the S190-640

A handy person from Washington DC Metro Area says:
Is the S190-640 a 6 lb spring? Also, how long is it? I have several coil balance springs that need replaced on double hung windows 32 x 62h and want to be sure these springs are long enough. The tallest window is 32" x 66h which I calculate will take two 640's on each side. The detents seem OK on all windows.

Not sure if I have single strength or double strength glass in vinyl insulated double glazed windows. Would it cause a problem to get coil balances that would carry more than enough weight? Instead of a 7lb an 8lb? Two coil balances that would carry 12 lbs instead of 11? If there are no negative consequences to getting coils a little stronger I will do that.

Please advise. k carter
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Paul from SWISCO responded:
Thank you for posting. Yes, our S190-640 is a 6 pound spring. Keep in mind that unlike other balance system, coil balance strengths add up when you calculate what you need to support your sash. For example, if you have a 12 pound sash, you will need two 6 pound springs.

As for the length, these springs usually stretch to 35". Would that work for you?

As for using springs that are stronger than what your sash actually is, I wouldn't recommend it. The window may not operator properly if your springs aren't the correct weight, even if they're a little stronger. You should stick with what was installed in the first place.
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