This letter is to see if you can provide some feedback and guidance to my spiral balance dilemma. We have a sash-type window that is overall 48" wide x 60" tall. The bottom sash and the top stationary window are approximately 48" wide x 30" tall. Servicing was necessitated because the right side pivot lock shoe broke and the bottom section of the spiral spring that has the two pins was also snapped off. The springs were the old style with the with pvc tube covering the coils. First, I went to Lee and Cates glass and they matched me up with a 83-28 spiral balance spring (28" with yellow busing). The installation went fine. Window slid fine. Upon fully bringing down the bottom sash window, the springs snapped out of their tubular housing. Then, I ordered online two springs from SWISCO - pn S900-28-Yellow, . I performed the same installation, and then these two SWISCO springs also snapped out of their tubular housing. After a few moments of taking deep breaths and trying to avoid using explicatives, it dawned on me that maybe the springs should be longer than 28", since the window halves are 30". So, maybe, the spirals are being dragged out of their tubular housing because the window moves down beyond their length. The older spiral springs were about a ¼ or so longer at the bottom section of the pin tabs, even though the coils and tube housing measured 28". That's why those springs, perhaps, never dragged out of the coil housing when the original installer tested them. Or, I'm speculating that the original installer happened to only have the 28" spring length in his truck, and ended up using these marginally shorter springs instead of making a second trip to return with the right spring lengths - they at least worked for him to initially test the window. We purchased the home brand new about 10 years ago, and rarely opened that window.
Question to you folks: Is there a table or guide available that shows the recommended spring length relative to the window sash size ? searched the Internet with no luck. I realize that it also depends on the weight and width of the window sash and probably other variables. However, it would be really handy to have such a guide. My home has 32 windows, and I expect springs to start failing at any time, and I would like to be able to do a sanity check on the spring lengths as I remove them and get ready to purchase replacements.
By the way, the original springs were screwed into the very top hole of the window frame. There is a second drill hole drill hole about an inch or two below the top hole. Should I try reinstalling the springs in the lower drill hole to make up for the shortness of these new springs and see if that solves the problem? It doesn't matter if we lose an inch or two on how far up the window could be opened.
Any daylight that you may be able to shed would be greatly appreciated
