9 lb Series 152 Coil Balance

You could always divide the weight up among more springs. If your sash weight exceeds 18 pounds, then you'd use 2 springs on each side instead of 1. 

The question now is just a matter of what you'd use. If you give me the exact weight of your sash, we can tell you what Series 152 spring will work for your sash.

Sure, I understand that. But your new glass makes the sashes heavier, which means that only 9 pounds of support on each side isn't enough. Your sash is no longer 18 pounds, so we need to figure out how much it actually weighs so we can get you the right springs.

The Series 152 is compatible with three different pivot shoes (15-175, 15-177, and even our 15-158), each of which can hold 2 springs. I don't know what you have, exactly, but odds are yours works the same way. I've never come across a pivot shoe that can only hold 1 spring.

We don't have springs that exceed 9 pounds on each side. I'm afraid your only option is to double up. This is a very common solution to the issue you're experiencing. 

If you wanted to be 100% sure, show me a picture of your pivot shoe out of the window and without obstruction and I can tell you what is compatible with it. I also still need the exact weight of your sash. Please be as precise as possible. It's important that we get the exact weight of the sash. Guesses won't do.

Ah, well here's one issue: you don't have the Series 152 spring. That pivot shoe is an older version of our 15-180, which is designed to work with our Series 190 instead. Both the Series 190 and Series 152 are 1/2" thick, but the Series 152 isn't supposed to work with your shoe. It may install fine temporarily, but over time you'd start to notice issues. The Series 190 is definitely what you want.

The good news is, your shoe can definitely take two springs. One screws on one side, and the other screws on the other side. You'd also need a new retainer for the extra spring; specifically, our 15-181 and an extra 15-182 bushing. You should be able to re-use your existing bushing but you can get two new ones if you wanted to be safe.

All we need know is the weight of the sash to calculate the proper spring strength. 

When I say one spring screws to one side and the other spring screws to the other side, I'm specifically talking about the shoe. If you look at both sides of the shoe itself, you'll see it has two screw holes.

You can stick with the Series 152 if you want, but I want you to keep in mind that there may be issues in the  future. The Series 152 is not designed to work with your window.

As for sash weight, since you already have two 9 pound springs then I suppose you could use two 4 pound springs, as well. You'd use one 9 pound and one 4 pound for each pivot shoe. Make sure they're stacked symmetrically; what I mean by that is, if you put the 9 pound spring on bottom and the 4 pound spring on top, make sure you do this for both sides. I think this should work.

The roller retainer you're talking about is called a bushing. I mentioned it back on the 15th. The bushing I recommended was our 15-182. I also mention here that you need a new retainer that can handle two springs. I suggested our 15-181. I highly recommend rereading my posts above to clear up any confusion.

If you want to go with the recommended Series 190 instead of the Series 152, then you should use one S190-540 and one S190-640 S190-840 on each side. Like I mentioned before, you want to make sure these are stacked symmetrically.

To install a second spring, you just screw it on and stretch it up to fit on the second peg on the 15-181 double retainer.

Ah, you're right, sorry. That was a typo. I meant to type S190-840 instead of S190-640. Hopefully that clears things up.

It was my pleasure! Thanks for ordering with us, as always, and please let me know how it works out. If you run into any issues then we'll definitely take care of you.