We also have some with different stamps - we have determined the spring type but unsure of the weight required. One is stamped 28S38. The other is stamped 2990 - 38. Can you tell us what weights we will need?
thanks,
Dave
Thanks for posting, Dave. Those stamps really should be the same. Can you give me the weight of your window sash and the length of the metal channel for your balances? That will help us determine the appropriate stamp.
I don't know the weights of the sash, but the one with 28S38 is 29" long,
the one with 2990-38 is 30" long.
thanks,
Dave
Without knowing the weight of the window sash, we cannot recommend the appropriate option. You will have to remove the sash from the window and place it on a scale to determine its weight. We need the weight to be as precise as possible, as well. Thank you!
I weighed the panels and they are approx 38 - 40 #.
thanks,
Dave