Replacement channels for ply gem windows

Thanks for posting. It sounds like you need new window balances, which are the tension mechanisms that regulate the opening and closing of the window. There are many different kinds, and I'm afraid I can't narrow down what you might have from this information alone. The best thing to do is to send us pictures of the existing hardware, removed from the window if possible. We may have more questions from there, but that will at least narrow down your possible choices. In the time being you can read more about all the balances we carry here. 

Hey there, Bob's not here today but I will do my best to assist you.

This photo is a huge help--can you verify that the window you found this on (54Hx 36W) is identical to the other window (36H x 30W), other than size? If they're the same make and model then we can reasonably assume that the type of balance used across all three windows are the same, differing only in length and calibration. 

Assuming so, then let's focus on the balance you do have. This is unfortunately not a standard configuration. What you have here is known as an "extended travel" channel balance, named for its unique block and tackle configuration. To put it simply, the pulley is built into the bottom shoe, rather than just the metal channel, and the cord has a much longer range than what you can buy off a store shelf.

We can supply these, but they must be a custom order, which means they're non-refundable. Considering we're trying to replace a balance without a direct reference, that means we're going to be working through a lot of uncertainties. Our recommendation will not be 100% guaranteed and there will be some risk with your purchase. I just want you to be made aware of that before we proceed.

With that in mind, please verify that this window is identical to the two windows that are missing their balances. Next, I'll need you to measure the height of the visible glass for both cases. You've given the overall sash height, but for channel balances we need to go by just the visible glass. I'll also need the precise weight of the sash in both cases. You can do this by removing the sash from the frame and putting it on a scale.

Next, we need to figure out which extended-travel balance this is. There are quite a few varieties. To start, remove the balance from the window and show me a clear picture of the top nylon fitting and the metal hook at the end of the cord. That last part is essential; it may seem like a small detail but its very important.

Finally, how many of each size did you need?

Once I have that information, I'll do my best to find you the best replacement part for the job.

Awesome! Sounds good. I figured they were the same configuration, but it's always good to be sure. Trust me, there are no end to surprises in the window industry.

I'll be here to help whenever you can get that data for me.

These photos are a huge help, thank you! I am very familiar with this balance type, so we're on the right track.

Concerning the 13" glass height that you measured, can you tell me if that's for the window that's missing its balance, or for the window that still has its balance (the 23 4 stamp in your photo)? 

Also, can you confirm that the metal channel length for this model (stamped 23 4) is 23-7/8"? It should be, but I want to be 100% sure.

Basically, my goal is to compare the difference between the metal channel length and glass height for the window that still has its hardware (Window A) and then apply that same difference to the glass height for the window that's missing its hardware (Window B). 

As a pure example, let's say the glass height of Window A is 20" and the balance is 21-7/8". Then we look at Window B and see that the glass height is 15"; I can reasonably deduce that the proper balance length would be 16-7/8" based on the difference established by the first window. 

Hopefully that makes sense!

Lastly, don't forget to get the sash weight for the window that's missing its balance. That will also be an essential detail. You'll want to get it as precise as possible, down to the ounce.