Dear Jim: I like natural ventilation spring and fall, but my vinyl tilt-in double-hung windows are hard to open and do not stay up. How can I make them operate like new again? – Cathleen H.
Dear Cathleen: Although double-hung vinyl windows, particularly newer replacement ones, are practically maintenance-free, they can gradually become more difficult to open and close without some fresh lubrication. You may also find once they are lubricated again that they may not stay up when opened. Correcting both problems is a simple DIY project.
Most vinyl tilt-in double-hung windows have a plastic pivot block at the bottom of lower sash. A pin at the bottom of the sash fits in a hole in the pivot block and this allows it to pivot open for cleaning. The plastic pivot block slides up and down with the sash in a channel inside the window frame. There is a counterbalance spiral spring to hold it up when opened for ventilation.
Over years of use, dirt collects in the channel causing more friction against the pivot block when you slide the sash up. As the sash slides up, the spiral spring twists and as it moves up a rod in its center. These are greased when new, but dirt and time can also create excess friction there.
The spiral counterbalance springs do not have an indefinite life and can fatigue, weaken and break after many openings. When this happens on a newer window with good lubrication, the window sash does not stay up. If there is so much friction from dirt and old lubricant in the channel, one of the springs may have broken and the sash will still stay open.
Slide the lower sash up a little to clear the window frame at the bottom. Push in the two latches at the top and tilt it in just as if you were going to clean the glass. Look in the channel on each side for the plastic pivot block at the bottom and the long spiral spring above it. Wipe the channel and pivot block clean.
Spray some solvent, such as WD-40, on a rag and wipe it over the long spiral springs to clean off all the old grease and dirt. It will be pretty black and dirty. It will be apparent if one of the two springs per window has broken. Apply some white lithium grease to the spiral spring. Spray some silicone lubricant on the channel and on the pivot block.
The window sash will definitely be easier to open after this maintenance. If it still is more difficult to open than when it was new or it won’t stay up, you should replace both springs in the window. You can try to just adjust them tighter, but chance area these old weaker springs will break after not to many more openings.
Lift the sash a few inches and put the wood block under it. Release the sash tilt latches and tilt it in until it is horizontal. Rock one side upward so the sash pin slips out of the blocks and place the sash on the floor. The plastic sash stops and spring cover snap off easily from the window frame. Weigh the sash. Unscrew the spiral springs and remove them.
The strength of spiral springs is indicated by the color of the plastic tip of the spiral spring. The colors are white, red and blue and they can handle sash weights of 4-12, 6-18 and 10-26 lbs. respectively. Use the same color new springs or the next stronger one if your sash weighs near the spring upper limit.
Measure the diameter and length of the old spring aluminum tube only, not including the tip, and order this length. New spring tube diameters are either 3/8 or 5/8 inches in diameter. The nominal 5/8-inch-diameter springs actually measure 9/16 inches.
Screw the new springs into the frame at the top again. Push the spiral spring rod up into the tube. Hook a charging tool (costs a few dollars at a hardware store) to the rod end and pull it down. You will feel the spring tighten. Give it an extra one or two turns and hook it into the pivot block. Put the sash back into the blocks, push it level and snap it back into the frame.
Follow the same procedure without unscrewing and removing the springs if you prefer to try to just twist the old weak spring tighter. Use the spring charging tool to give the springs a couple extra turns for more strength. This should hold the windows open.