Correct identification of side window balance

A quick learner from Portland, Oregon says:
Hello. I believe I need a Series 350 with 19-002 Top and 15-004 shoe. The length of the metal is 32 inches. It is stamped with "31B". My sash weighs 22 pounds. I'm looking to replace the balances because when opened all the way, the sash droops down by about 8". Since I'm having this problem, and my sash weight is near the top of the range for the 3130, can you advise if I should order the 3130 (16 to 23 lbs), or go with the 3140 (weight range 23 to 28 lbs)? Based on the attached photos, can you also confirm that I have the 19-002 and the 15-004? Thanks very much.
-- Kurt
User submitted photos of a window balance.
Profile picture of Paul
Paul from SWISCO responded:
If your sash weighs 22 pounds, you should go with the 3130 option. It's likely your sash droops down now because your spring is worn down. It is, after all, possible to have a balance that is too heavy, so going any higher could cause complications.

I agree that the Series 350 is similar but you will need to compare your measurements to ours to be sure.
A quick learner from Portland, OR says:
Hello, Paul. Thanks for your reply. Okay, I will go with the 3130 option. Regarding the correct shoe, I think I actually have the 15-005. Please see the attached photo, where I show 1" from the back side of the flange. On the dimensioned photo on the web site, I can't tell if the 1" (or 1-3/32" for the 15-004) is measured from the front side of the flange or the back side. If I do indeed have the 15-005, then I have a 19-002 top and a 15-005 shoe, which doesn't seem to match any of the Series. Please advise! Thank you.
User submitted a photo of a window balance.
Profile picture of Tom
Tom from SWISCO responded:
I think that you have the 15-004. When measuring the depth of the shoe, you measure the entire depth, flange and all. You must also account for wear; that is, you have to keep in mind that your depth is likely a little less than it was originally. Considering these factors together, the 15-004 seems like the optimal choice.

Plus, in the off chance I'm wrong, you can always just sand the 15-004 down a little until it fits.
A quick learner from Portland, OR says:
Okay, Tom, sounds good to me. I'll go with the 15-004. Thanks for the prompt response.
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