A home owner from Danville says:
November 23, 2015
I am trying to order replacement window channel balances. I have identified them to be series 385 (15-005 on top and 14-004 on bottom). They are 1/2 inch. one window is 39 1/2 by 29 and the other is 29 3/4 and 33 1/2. Would the same size balance be used for both windows? The length of the balance is 26". I am also wondering about the weight. One window is roughly 20lbs and the other is 18lbs. The one that weighs 20lbs has the markings on it " 25 3 CO Caldwell. I'm not sure to order the 2530 or the 2540 since it's only a pound difference?
Paul from SWISCO responded:
November 24, 2015
If one sash is 39-1/2" wide by 29" high, and the other is 33-1/2" wide by 29-3/4" high, then you can use a 26" long balance for both. Regarding the spring weight option, a 2530 should be sufficient for both sashes.