balance spring

Question

I am trying to find replacement balance springs for my windows --
my windows are single hung
the windows were manufactured by Lighthouse Windows (distributed by Norandex in 2002) - the builder was Lennar
the sample I have measures: 1/2" x 1/2" x 27" (the metal part - not counting the plastic tips)
there is a number etched on the metal -- it looks like 2640
(I say looks like because the "6" is not clear -- I think it's a "6")

Tom · Accepted Answer

Welcome to SWISCO.com. I'm going to quickly run through the process for identifying a channel balance.

Step one: Identify the Series. Are there bent tabs or "wings" on the top and bottom plastic pieces, exactly like our 15-004 shoe or 19-005 top guide? If so, you need Series 380 or Series 385. The Series 380 can be identified by its 1" bottom shoe. The same shoe on the Series 385 measures 1-3/32" like the photo below. Choose the Series that matches your balance.

Step two: Choose your length. Your measurement of 27" matches a potential stamp of "2640". This refers to S385-27 or S380-27.

Step three: Choose your option. 2640 appears to be correct, but you can weigh the window sash to be sure. 2640 is the option for windows between 19 and 26 pounds.

And that's all you need to place an order.

Alternate view of 15-004