Replaceing Balance Spring Side Load Single Hung Window

A quick learner from Orlando, FL says:
October 21, 2015
Have 2 separate window balance springs need to be replaced, 2 windows with the same markings and the other a different one. Markings are on one is 26D and the other 28C no other markings.
User submitted photos of a window balance.
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Tom from SWISCO responded:
October 22, 2015
Thanks for posting. This looks like our Series 380 channel balance. Check it out and let me know if you agree.
A quick learner from Orlando, FL says:
October 22, 2015
P.S. Have not weighed them yet either how accurate must I be? If close should I go up to next weight class?

Thanks again
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Tom from SWISCO responded:
October 22, 2015
We don't recommend going over what you need. A balance that is too strong could cause complications in operation. A stamp of 28C usually corresponds to our 2830 option, but weighing your sash to confirm is a good idea.
27" Series 380 Channel Balance
27" Series 380 Channel Balance
S380-27
$10.55
29" Series 380 Channel Balance
29" Series 380 Channel Balance
S380-29
$11.10
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