Custom S400-23 balance
We placed an order for the red tip balances but realized when we went to install them that the sash is less than 7 pounds. We're going to return the 8 balances that we bought and will need a special order link to purchase 8 more of the balances with less strength. We'll get back to you with the exact weight once we're able to weigh the sash. Thanks!
I'm afraid the Red color tip is the weakest available option for this size balance. It also appears that your original balances had red tips, as well. Did you try installing our balances? I believe they should have worked.
This is definitely a weird case. The red tip should be perfect for your sash weight. When charging the S400-23, did you make sure to charge it with the bow tie end tip as close to the red nylon bearing as possible? If it was sticking out too far, that may have messed with the tension. In my experience, if you charge with the spiral exposed the tension never seems to be correct. Whenever I've done this in the past I always end up having to recharge it.