[Brad-DIY]

I only get cold OR hot water from my Kohler mixer valve in the shower.

For all of you who may have a Kohler mixer valve on your shower I have some insight of the potential problems you may have. My valves are circa 2005 and are NOT Positemp valves. This Kohler pulls out to turn on water and then the handle swings CW and CCW for hot and cold. You've all seen the mixer valve and mechanisms and how to remove it by taking out the locking pin etc. replacement cartridge is $20. On this valve body there are two side valves for use when repairing the innards without having to shut off the mains. Use a blade screw driver and turn CW until these are secure. It should take about 4 turns to bring back to the open position when you're done and to return it to service.

Okay, the biggest problem with this model of valve is not the mixer cartridge, but a pressure moderator mechanism. This item sits behind a 3/4" diameter slotted (blade screw driver) cap located between the cold isolation valve and the main handle stem (center line of valve) - you can't miss it. After unscrewing this cap take a large pliers and grip the cap gently pulling it all the way out of the housing.

You have the brass cap with its neck snapped onto a stainless cylinder that has holes around both of its 2 mid-sections, and a snapped on end cap. There is a floating piston inside this stainless cylinder that has gotten stuck due to a fine calcium build up. If your hot OR cold water doesn't come out of the shower, this is the culprit. If you only looked at the mixer cartridge you wouldn't think anything was wrong. If you have dripping or leaking, the mixer valve would be the issue.

If this internal piston doesn't move in the cylinder you'll need to take it apart and clean it up. Without bending anything, carefully take a blade screw driver and pry off the loose stainless end cap (easy) and the same for the brass head on the other end. Next, place the cylinder vertically on the work bench and remove the piston using a small hammer and punch. Center on the piston and break loose - flipping the cylinder back and forth. Once the piston is out of the cylinder clean all interface surfaces with 600 wet sandpaper until the piston glides nicely through the cylinder. Coat with plumbers grease and reassemble. The piston is symmetrical and can be inserted either way, but the cylinder is polar. The longest section points towards the brass end cap. Reassemble the valve and you're ready. Plumbers grease on O-rings.

[Milo Dolezal]

Thank you sharing. Milo