Broken tension string in window Channel balance

Home Owner from CA
Hello, one of my window channel balances recently broke (the tension string). How do I go about ordering the correct one?

There are no markings other than the numbers and letters listed below:

28.5 GX CMC 11

The metal part is about 28.5 inches and the width is 1/2". Thank you
A customer submitted image of their channel balance attachment.
10 Replies
Tom
Tom from SWISCO
SWISCO
Expert
Hey, thanks for posting. I've narrowed this down to two possible channel balance Series: either our Series 380 or our Series 385 balances.

Now, as you can see, there is only one difference between these two Series, and that is their bottom shoe. The Series 380 uses the 15-005 while the Series 385 uses the 15-004. I can't quite tell what you have based on your pictures, though. Please carefully compare their dimensions to your own hardware and see which is a better match.
Comparison of 15-004 and 15-005
Comparison of 15-004 and 15-005
Home Owner from CA
Ok. Thanks. I've narrowed it down to 15-004. Now which option do I choose for the sash weight? Thanks. Is that what the "11" means on the stamp of the channel balance? The full stamp says "28.5 GX CMC 11"
Tom
Tom from SWISCO
SWISCO
Expert
I think the 28.5 is what you should consider, though usually there isn't a decimal. That tends to correspond with our 2850 option. However, I recommend that you weigh your window sash just to make sure that this is the correct choice.
Home Owner from CA
Ok I've received my 15-004 order.

One problem and its a good up on my end. Everything is fine except the original metal channel measures 29" and the ones I purchased were 28".

I installed the new 28" ones and they seem to work fine. Any negatives I should know about the 1" difference or would it be ok?

Thank you!
Tom
Tom from SWISCO
SWISCO
Expert
Hmmm... there could be some problems later on down the line. There may be too much pressure put on the spring. They may be working fine now, but keep an eye on it. If you feel any resistance, then it could be a sign the balances are failing.
Home Owner from CA
Thanks for the reply. I'm going to return them and get the 29". It might save me some trouble in the long run. I also think I ordered the wrong weight for my sash. It's a bit more difficult to close. My sash weighs 35lbs. Which weight option should I choose for the series 385 with 15-004?

Thanks
Tom
Tom from SWISCO
SWISCO
Expert
For the S385-29, I recommend the 2860 option. Two balances with this option can carry a window sash weight of 32 through 35 pounds.
Quick Learner from Smithfield R.I
How do you restring a Channel Balance string? What's the proper diagram string pattern for the string to control my channel balance. Thank you,
Tom
Tom from SWISCO
SWISCO
Expert

It is a standard practice in this industry to advise customers to never try to restring their balances. There is no guide or diagram for how to do this because it is absolutely not something you should attempt; these balances are under a lot of tension at all times and attempting to change out or alter the block and tackle system in any way leads to a huge risk of injury. I've seen it happen with my own eyes. Take my word for it: it's not worth whatever amount of money you're trying to save.

If your string is damaged, you need to buy a new balance. Every window shop from coast to coast will tell you the same thing. It will be easier, safer, and in the long run it will be better for your windows, too. Even if you were to successfully restring your balance, the tension would never be the same and the balances still won't function like they used to.

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