Need to Identify Sash Spring Weight

Question

I have a window with a broken sash coil balance, and another clearly about to go. The window is made by LBL, who has gone out of business. The sash coil balance appears to be similar to the a Series 180 Coil Balance, but I do not know the spring weight. The spring marking appears to be 4HI; see photo. Although not shown in the photo, the coil balance does have 2 holes, like your Series 180.

Are you familiar with this spring, and do you know what weight would be appropriate?

Unfortunately, the sash is not easily removable, so I can not weigh it. The pivot shoes do not have slots that would allow the sash to be removed; it requires disassembling the sash which I am not comfortable doing. (I am attempting to purchase the parts ahead of time so the window repairman does not need to make two trips.)

The overall window is a 24W x 27H, the sash is double pane, 20-1/2W x 14-1/2H. Hope you can help and expedite this. Window has been like this for three weeks and I have a bad shoulder after surgery. Thanks

Tom · Accepted Answer

Thanks for reaching out to us. It is very possible that you need the 4 pound spring, but that's just an educated guess. You will need to remove the sash and weigh it to be 100% sure.

That should not require disassembling the sash, either. I've never worked on a tilt window where that's necessary, especially windows that use the Series 180 assembly. You should be able to tilt the sash in and then twist it out to get it free of the pivot shoes, regardless of whether or not there are slots. You will have to do it anyway to replace the balances so it is something you have to address eventually.

If you can weigh the sash, then you just have to divide that weight by how many springs support it. So for example, if you have one spring per side and assuming 4 pounds is right, then the sash should only be 8 pounds. If you have 4 springs per side then the sash would be 16 pounds, and so on.