Searching for size of spiral balance for nontilt windo

A quick learner says:

I'm trying to fix an old window. It is the lower of two sashes, typical old double-hung kind, but no sash cord! No pulley. It used to have a spiral balance. It's in a room with many similar double-hung sash windows, but they all have pulleys and sash cords! This one has a trench in the side of the sash, and used to have a spiral balance. It is 25 1/4" high itself, from bottom of sash to top of sash, and the window from sill to top is 48"

What should I order? Obviously I need two spiral balances plus some hooking part to be attached to the bottom of the sash.



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Paul from SWISCO responded:

Hello, Paul. I believe you are describing a wood window that was using a Series 500 non tilt spiral balance. If I'm right, can you tell me the visible glass on the bottom sash? (width" x height"). 

A handy person from Arlington, Mass. says:

it is 26 ½ wide and 21 ¾ high, the visible glass

I believe I need to order two spiral balances, plus two little brackets or something to attach the balances to the bottom of the sash. At the top, to the side of the window frame, we just screw in, right?

Also, do I need to get a little tool for adjusting?


Paul G.

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Paul from SWISCO responded:

Thanks, Paul! The formula we use to determine the size of the balance for the lower sash on a wood window is to add 3" to the height of the glass. You gave 21-3/4" for the visible glass, so the size of the glass is likely 22". That means I recommend the S500-25". 

You are correct, you want a bracket to cradle the sash from underneath. That would be our 17-012. Additionally, the charging tool is the 75-005

Have the bottom sash rest on the sill while you work the S500-25 balance down through the top of the sash and screw the balance tube at the top of the window track. Do the same on the other side. Now raise the sash; the spiral should have unraveled from the balance tubes, but if not hook your tool to the bottom hole of the spiral to help it. While someone is holding the sash up take a 17-012 bracket have the end cradle the spiral and screw the bracket to the bottom sash rail. Do the same on the other side. 

Have your friend continue to hold the sash up while you bring the spiral up with your finger at first, then as you get close to the bracket, hook on the spiral with the tool and give the spiral three or four turns clockwise. You should feel the tension building. Now hook the spiral bow tie to the bracket. Repeat for the other side one last time. Now try the sash. If it still feels a little heavy, unhook the spiral from the bracket and give the spiral another turn.

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