channel balance No. 2840

Thanks for posting. I'm afraid you have not given me enough information to identify your balance. It sounds like you have a 29" block & tackle balance with a stamp option of 2840. Now you just need to pick out the top and bottom fittings in order to determine the Series.

I recommend that you look at our Channel Balance Home Page and follow the steps in order to find the Series that best matches what you have. See the video below for installation instructions.

The difference between the 15-004 and 15-005 lies in the size. Check out the image below to see which one is closer to your own. Don't worry about the color, that doesn't mean anything in this instance. Size is all you should be concerned with.

Keep in mind your size may differ slightly due to age and wear. Use your best judgement.

You also shouldn't worry about spring length. The strength of the spring is decided by the stamp option. Yours is 2840, and two 29" balances with a 2840 option can carry a window sash weight of 23 through 28 pounds. So rather than measuring the length of your spring, you should be weighing your sash. That is the most reliable way to determine what kind of spring strength you need. Remember, spring strength is always denoted by the stamp option.

I know it seems complicated, but it's really simple once you understand what to look for. For future reference, when finding a replacement channel balance, these are the steps you should follow:

1) Determine the Series by matching up the attachments on either end of the metal channel. Sometimes they're nylon guides, sometimes they're metal clips. Regardless of what they are, there are many different varieties that all seem sort of similar, so you will have to carefully measure them to know what you have.

2) Determine the length by simply measuring the metal channel.

3) Determine the spring strength by referring to your stamp option. If your balance does not have any stamp, then simply weigh your window sash.