window channel balance problems

Question

I have a non-tilt window that operates with great difficulty.  I removed the sash, removed the channel balances, lubed them and replaced.  The window works better, but the left channel balance squeals and catches or kind-of ratchets like there is a stuck or broken part somewhere on a pulley wheel.  The metal channel measures 28 inches.  The stamp says "27 3" with "BS1" sideways and a small "OC" beside that.  The top and shoe look like the ones on your series 350.  When I re-installed the channel balances, it took a lot of pulling to re-tension the spring.  Seems like it should work a little smoother.  I am guessing I need the 2703.  Any help?

Tom · Accepted Answer

A stamp of 27 3 usually corresponds to our 2730 option, but you may want to weigh your sash just to be sure. There's a chart on the S350-28 store page that tells you how much weight each option is meant to support. Either way, it definitely sounds like you need new balances. Figure that this kind of hardware has a lifespan of 5-10 years, depending on how often they're used.