Coil Balance for Bathroom Window - only stamp on coil is an "F"

A home owner from Bay Shore, NY says:
I had windows installed from a company called Thermo-tite Windows about 10 years ago. They are now out of business. The coil balances have broke numerous times over the years and each time I would have someone come from Thermo-Tite to repair the window.

From what I see, the balances I have resemble your Single Coil Tilt Balances - Series 140. I have included a few pictures which are attached. I need balances for both the right and left side of the window.

Our window measures 24" W x 17" H x 1.5" D. I cannot weigh the window exactly, but if I had to guess I would say it weighs about 5 Lbs. The channel that the balance runs in is about 15" long give or take.

Let me know what you think. I would like something that will last. As I mentioned, the ones used by Thermo-Tite broke numerous times. The coils basically snap after a given time.

Thank you,

John
User submitted photos of a window balance.
Profile picture of Paul
Paul from SWISCO responded:
Hey, John. Before I can confirm that the Series 140 will work, can you first show me a picture of the pivot bar that links with the pivot shoe? Thanks!
A quick learner from Bay Shore, NY says:
Hi Paul,

OK, I will need to get another picture from home, so it will not be until tomorrow. I can tell you it is a tilt window that is removeable. Basically there are pegs on both sides of the window that are oblong and fit into the shoe. You insert the pegs into the shoe, tilt the window up and that locks them into place.

Thank you,

John
Profile picture of Paul
Paul from SWISCO responded:
Thanks! Yes, those pegs are the pivot bars and they are what I need to see. I just need to confirm that they will also fit in the Series 140 shoe.
A quick learner from Bay Shore, NY says:
Hi Paul,

Here are the pictures of the pivot bars. I also included one of the empty shoe.

Let me know what you think.

Thanks,

John
User submitted photos of a pivot bar & shoe.
Profile picture of Paul
Paul from SWISCO responded:
Ah, I see. Unfortunately, your pivot bar won't fit in the S140-6 balance system. I think you should consider a different setup.

Look at our 15-177 shoe, S152-6 spring and 33-072 screw, which can attach the coil spring to shoe. Do you think this can replace your hardware? They discontinued the coil spring you have now, but this hardware may work as a substitute.
A quick learner from Bay Shore, NY says:
Just to confirm, are you saying what I currently have is something you used to carry?

Also, would I keep the top support that I currently have, as shown in the first picture above? If so I believe what you are saying will work. However, do you carry a coil that has the hook on the end, as shown in the 3rd picture above. That is how the current coils attach to the shoe.

...and while I have you, as I mentioned I have had trouble with the coils breaking in the past. Is it better to go heavier with the coil in order to prevent the breakage?
Profile picture of Paul
Paul from SWISCO responded:
The manufacturer discontinued your type of hooked coil spring and went with the screw on type, which is why I am recommending the 15-177 shoe, S152-6 spring and 33-072 screw. You can reuse the coil spring housing if you want, I don't see any problems with that.

The spring strength is determined by the sash weight. You shouldn't go stronger or you can have trouble operating your window. These are precise systems and you only want springs that are just right.
A handy person from Flushing says:
I have the same type from the same stupid Thermo-tite Windows and both my coil spring and the housing are broken. What housing do you recommend as a replacement?
Thumbnail of the uploaded file named IMG_9382.jpeg
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Tom from SWISCO responded:

Your exact housing style isn't made anymore, unfortunately. Seeing as how you have a 15-177 pivot shoe, that means you're using the Series 152 spring. As of this date, there is only one cover that's compatible with this spring, and it is sold in three separate components: see our 15-143 bushing, 15-144 bushing cap, and 15-145 support barrel.

The barrel goes inside the spring to keep it steady, and the bushing and bushing cap then snap over it to form a kind of cartridge.

Hopefully that makes sense. Please feel free to reach out if you had any questions.

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