18 inch sash balance

Thanks for writing in. Confirm that the metal channel, not including the end attachments, is 18" long. If so, see our S351-18 or S390-18 Channel Balances. The only difference between these two balances is the 'depth' of the bottom nylon shoe, so compare both your old balance and see what matches closest. You will need to select a stamp option. If there's no stamp code on your balance's metal channel, weigh your window sash. You can then match that exact weight with one of the weight ranges listed along each stamp option on the product page. 

Thanks for your reply. So for your stamping of "17 5" you will want to go with the 1750 option that holds a spring weight of 17-20 pounds. The weight you indicated sounds like you may have weighed the actual balance instead of the sash. Look over both balances I mentioned in my last response to see which one would make the better match. You also mentioned take out clips. Does your clip look something like our 16-002? Take a look. If so, then you should be ok with going with that clip as a replacement.

Thanks for getting back to me. Hm, I'm not seeing anything particularly amiss in these photos. Could you compare this installation to an identical window in the house, and see if it differs in some way? Many thanks.