Balance string is twisted, want to replace

I'm not sure what you have, unfortunately. We have dozens of different balances with that stamp. It's not a product code or anything, it just indicates the strength of the spring.

In order to figure out what Series this is, we need you to remove an undamaged version of this balance from the window and show me clear pictures of the top and bottom nylon fittings. We will also need to know the dimensions of these fittings.

Thank you! I recognize this balance. You have a special type that will have to be a custom order. Can you confirm the length of the metal channel? It should be 26-5/8", not 27". Can you also tell me how many you need?

Once I have that information, I can email you an order link and price quote for that quantity.

Thanks! That's just what I needed to see. Please give me just a little time to confirm the availability of this custom balance and I'll get back to you before the end of the day.

I'm also not sure what clip it is you're referring to. Can you show me?

Gotcha. These clips are physically part of the balance and will be included with the custom order we set you up with. I'll get back to you on that once I have confirmation.

Hello again. I just had one last question: can you confirm that the stamp you gave us in your very first photo is off the same balance as you're showing us in the rest of your photos? I'm having a little trouble with that. There is a chance you're showing us two different balances.

Hello! Did you see my most recent post on the 11th? We ran into a road-block in our research and I wanted you to confirm that information before we proceed.

Okay, this explains a lot. This is an entirely different balance. To clarify, you're telling me that this is used in the same window as the balance you showed us on the 10th? If so, then that's wrong. Someone messed up at some point while repairing your window and used the wrong part. A sash needs identical balances on both sides.

I also should point out that the metal clip you're indicating in this new batch of photos is the take out clip, which is our 16-002. That's a different clip that serves a separate function from the clip you circled in red on the 11th. That part an attachment clip that holds the other balance to the frame. It actually does the exact opposite of the take out clip.

So, this presents a unique problem. I don't know which balance you actually need for your window. One of these is wrong and should not have been used. Would you happen to know which balance is original to your window? Like I mentioned before, the balance you showed us on the 10th has to be custom made. This other balance here doesn't. This is just a regular old stock part, probably either our S380-27 or S385-27, depending on the depth of the shoe.

It was my pleasure. I'm just sorry we can't give you a more confident answer. All I can tell you is that we can definitely replace either balance you show us here; I just don't know which one's correct. It would be a coin flip on our part. 

If you're the original owners of the house, then the window installers are definitely in error and in my opinion should be accountable. To be more specific about the differences between these balances, the one you showed us on the 10th has a different length (ending on a 5/8" measurement rather than a full inch) and has an extended cord travel length. It also has various stylistic differences in the bottom nylon fitting, such as the pulley wheel being built directly into it. I would be shocked if this window ever worked properly.