Sorry to take so long getting back. Hurricane Irma kinda slowed things down in So Fl. Yes your rite the metal channel is 32" long. There are no markings at all on the metal channel. I can tell you the springs are 19" long and 1/2" dia. I guess I may have to weigh the sash if need be. I wanted to start replacing all the window balances. Different sizes about 20 windows. It looks like it might be easier to order all the tops and bottoms pieces so I'm only removing window and hardware once. Do you sell a string and pulley kit.
Thanks for getting back to us! Yes, if there is no marking on the balance channel then the only other way to determine spring strength is knowing the weight of the sash. Replacing the top and bottom nylon pieces is totally doable, if those are the only things that are damaged, but I'm afraid it's not possible to replace the string and pulley system. If those are broken, you need an all new balance.
When I get a chance I will weigh the one large window, order the balances and see how it goes before doing all of them. So just measuring the spring does not help? Thanks
Correct: weighing the balance does not help.