new glass made my sashes heavier, what springs do i need?

A contractor from Detroit, MI says:

I have the same system as your 15-180 shoe and Series 190 coil spring 

I have replaced the glass in the window but it is now heavier than the original glass and the coil balances will not keep the sash up. 

 There are two different saah, one weights 24.6 lbs and the other weights 13.6 lbs. What coils would I need for each situation? (The heavier sash original coil has an 8 stamped on it.)

also, it does not appear that there was a coil bushing originally. Is a bushing necessary? Thanks, Randal

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Tom from SWISCO responded:

Thanks for posting! These sash weights are a little bit awkward for coil springs, but I think we can fudge the numbers a bit to get a setup that will work for you.

For the 24.6 pound sash, I recommend using two 6 pound springs (S190-640) on each side of your sash, which would total 24 pounds of support. That should be enough, even if it's a little under.

For the 13.6 pound sash, I would go a little over by using one 7 pound spring (S190-740) on each side. Like the other window, that should still work even if it's a bit off.

Some other hardware you might need: I recommend our 15-181 double clip for the 24.6 pound sash, which will use two springs on each side, and our 15-186 single clip for the 13.6 pound sash, which will only use one on each side. If you don't already have them, I of course also recommend our 15-180 shoe and 15-182 bushing.

Let me know if you have any questions!

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