Window slide/balance/lifter things
Hello, thank you for posting,
It appears you have either the Series 351, with a 15-002 bottom attachment, or Series 390, with a 15-001 bottom attachment. Take a look at the image below to determine which balance you'll need.
Based on your original balance, you will need a 28" balance with a 2730 stamp option that can support a 13-19 pound window sash.
If you feel that the windows were difficult to open or close, I would recommend weighing the window sash to make sure it falls in the weight range above to confirm the correct spring strength was used. Let me know if you have any additional quesitons!
If the spring is too strong, it can create too much tension and cause the window to be harder to close or not close all the way. It can also lead to the balance breaking or causing damage to the window. Let me know if you have any additional questions.
