OK... we have 2 bathrooms upstairs. One is shower only and one is bathtub/whirlpool only. Shower and both sink faucets give scalding hot water, but the tub only gives lukewarm water. I know it sounds absurd, but it seems a tiny bit warmer if someone has recently taken a shower in the other bathroom. It is a one handle knob that turns far left for the hottest water and of course the farther right the colder. No matter where the lever is turned the water stays the same temp except for a surge here and there of cold. My husband thinks it's the mixing valve, but has no idea how to fix it. Can you help me? My little girl and I just want a hot bath... please! :(

Hey elders... Do you have a name on the valve.. or the shower head? How old is the house/bathroom?

And water temp in house really shouldn't exceed 120 degrees F. I mean.. 125 degrees F o.k. but any more is simply unnecessary and unsafe! Cheap fix to purchase a thermometer that can read at temps of 100 to 160 F and see what temp. your hot water is at the shower and the kitchen sink (they will be different)... thermometers sold at home supply stores or a local plumbing supply house at the parts counter (candy thermometer may also work). If over 120 let us know sources of hot water so can help you to reduce temp. save money, keep little girl safe!! :)

Get back to us with answer to questions I asked and will see how to advise from there.

If my answer helped please RATE THIS ANSWER by clicking on rate this answer at above right. Thank you.

Your husband is correct, it's the mixing valve. Do what MASS suggests and insure the initial temp isn't over 120 but we can help your husband if we know the brand of shower valve. There are some general descriptions we could give but a name really narrows the instructions.

Thanks, I am definitely having my husband check the water temp for safety. The brand of shower valve is Moen. Does that help?

Hi elders. A moen faucet... huh? That is good news for you. That is, moen warranties all parts for life! If, at the end of this, you guys need a part call 1800buymoen and they will ship you a new cartridge (or any other part) within 24 hours (usually) free of charge (including shipping it to you).

I wonder if you have a model number of the valve. That would be great!

Anyway, to start, have hubby remove the handle (by screw or by allen wrench) and see if he can see an adjustable temperature limiting stop. It will be plastic with a screw attached... maybe that needs to be readjusted.

Other than that I think it is time to remove the cartridge and check to see if hot water flows well.

Here, click on this link and will show you guys how to remove/replace the cartridge.

Installation Help / Animated Tutorial - Installing the Moen 1225 / 1200 Cartridge


Then shut water, remove cartridge, clear lines of any debris (may need to pulse the water on and off at shutoffs to clear debris... hold rag over valve to catch water/debris). Then reinstall cartridge... or install new cartridge and test away.

Check out the moen site (MOEN Kitchen Faucets, Bathroom Faucets and Bathroom Showers) and see if you can find your model number... then if you want call them at number above and they will send you instructions on your particular model... then you have them for life!

Let us know how it goes.

Most of us love Moen because of the warranty and ease of installation and repair. Many use the same cartridge so we don't need to carry 20 different types. Love MASS's link to the tutorial, I will keep this one . Thanks

Hey Mass, thanks for the great advice and instructions. My hubby ordered the part from Moen, so will keep you informed on how it goes. Thanks a ton. You just saved us a ton of money!

Hey we are glad to have helped here.. keep us posted!