Dan from Toronto, Ontario writes: "I saw your show about installing the Moen Positemp shower system. We had two installed, one upstairs and one in our basement shower. Both work fine for controlling the "shock" factor, but we can't seem to get enough hot water out of the upstairs one. Is there a way to adjust the ratio of hot to cold water at the valve?"
Yes there is. First of all, for those of you who don't know what this "pressure balancing valve" is, you might want to check out the animation "Shower Shock".
Moen has two types of pressure balancing valves, one that if you pull on the handle it will give you more or less volume, turn the handle left or right and your get hotter or colder water. The other one has only one full volume, and then you move the handle left or right for the temperature. On both models, there is a hot water limit setter designed to prevent scalding. In fact, if you really rely on this limiter to protect someone like grandpa, you may want to set it in the summer and then change that setting as the cold water gets colder in the winter.
Take off the handle. You will see a metal plate as in the first photo that is hitting against a white plastic stop. In the second photo you see that stop more clearly. Simply pull out the outter half of that white plastic stop, and re-insert it with the stop further to the left, and you will have more hot water.
If you have the full flow model, and need more water, Moen has just come out with a new cartridge with larger holes in it, allowing for more flow. So you simply replace the whole cartridge.
If for any reason you need to take this valve apart, or anything apart for that matter, you really should use a felt marker as you take it apart to guide you in putting it back together. In the case of this Moen faucet, you will want to mark the position of the hot water limiter. But there are three different parts that can be put in one way up or the opposite side up, giving you a total of 9 different possible combinations. That can be very frustrating. By marking during dis-assembly, even if you are putting in new parts, you can follow your marks.
Mark that metal part that holds the handle. If you put in on up-side-down, which is easy to do, the water will not go from off to hot, but hot to off to cold as you rotate it around -- a very confusing handle indeed. Then the brass stem that sticks out can be turned with the one flat on the top, or the two flats on the top. Getting that backwards will also create strange functioning of the handle. Finally the cartridge itself can have the tap that says H/C on the top, or on the bottom. This is made that way to allow you to reverse the pipes coming in just in case they were connected backwards to the household piping -- which does happen. Mark the top of each of these, mark a line across any two pieces that need to match -- and you will find you will be able to re-assemble it right the first time.