weight bearing on channel balance

Question

Hi. The stamp on the channel balance I need to replace says "25 4" which would seem to indicate your 2540, which is for a 19-25 lb window. I weighed the window, and it is 17.6 lbs. This window (and its twin) have been hard to open/close. Would it be better to replace with a 2530, which is indicated for a 15-19 lb window? Or continue with a 2540 per the original?
Thanks.

Tom · Accepted Answer

Great question! If your window was hard to open, and the stamp on the balance does not match the weight of the sash, you may have had a less-than-ideal stamp option on your previous balances. The weight of the sash is a far more accurate predictor of the stamp option; go with 2530 for a 17-18 lb door, even if it doesn't match what is stamped on the old balance. Need any more info?