380 series verses 385 series

A contractor from Oxnard, CA says:
I found your post about the difference between the 380 and 385 series balance.

Paul from SWISCO responded:

"May 21, 2012

Thanks for posting. Please look at the respective part pages for the 15-004 and 15-005 balance shoes, which are for the Series 385 and Series 380, respectively. Do you see how each is of a different depth? The 15-004 is 1-3/32" deep, while the 15-005 is 1" deep. Which one more closely matches your own part?

How exactly are you getting these measurements ? Is that the length of the end or the thickness of the plastic end ? thank you for any help you maybe able to provide. I also enclosed the marking on the rail if that helps.
User submitted photos of a window balance.
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Paul from SWISCO responded:
The correct way to measure the depth for these shoes is shown in the second picture you posted. It looks like yours is a little over an inch, which makes me think you may have our Series 380 channel balance. Is that right? Does your shoe measure 1-3/32" deep?
A contractor from Oxnard,CA says:
Thank you Paul for your response to my question. Yes it is a little over an inch which I guess is your 1 3/32.
I also read another comment saying after they installed new sash balances the window would only stay all the way open and was not able to keep it half way. I figured I had better remove the window and weigh it to double check the strength. My window weighs 18.6 lbs should i go with the 2950 or something different? Thanks Sean
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Tom from SWISCO responded:
Thanks for getting back to us. Before I can confirm the proper strength option, can you confirm the length of your metal channel? Based on your stamp, I think it may be 30", but I would like you to double check that, as well.

If so, then you were wise to double check the weight of your sash. For 30" Series 380 channel balances supporting a window sash that weighs 18.6 pounds, I'd recommend the 2930 stamp option. This can support a sash weight of 16 through 23 pounds.

It's odd that your original balances had the 29 5 stamp. Did you ever find it difficult to raise or lower your windows?

Please keep in mind that the weight range information is based on 2 balances per sash. Balances are designed assuming friction in the jamb weather-strip will carry a portion of the sash weight. Suggested sash weights are approximate.
A contractor from Oxnard, CA says:
Hi Tom,

Yes we have had many windows next to impossible to
close due to the spring being so strong. I also noticed yesterday one of my window frames being broken where the sash balance hook clips into. Do you know if there is an easy fix for this problem or would the whole window frame have to be replaced. Oh yes the sash balance is the 30" as you figured. Thanks Sean
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Tom from SWISCO responded:
Thanks for getting back to us, Sean. Unfortunately, I am not sure if we can help you repair your broken frame. Depending on the damage, you very well may have to replace it.
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