My water cycles hot, then cold, from the hot faucet. I at first thought it was my water heater, but I replaced the thermostat on it and cleared the water heater. When replacing the thermostat, I cut off incoming water to the water heater. I was thunderstruck when I saw that my kitchen faucet still worked, hot and cold. Please help me, it is annoying me very much!

Is it possible that you have a water heater and a tankless coil off your forced water boiler..

It is possible that you cut supply into heater but not into tankless... depending on how it was piped (if you even have a tankless coil on boiler)... and that could cause fluctuations, etc.

It could be that the cold water DIP tube in your water heater is bad..

Possible you have an indirect water storage system.. Not a water heater..?

Also possible that somewhere in system you have a check valve that has gone bad (gotten stuck)... or you could even have a defective mixing valve.

Need you to really look at your system... shutoffs... bypasses... boiler feed, tankless coil, check valves, water heater inlet/outlet, mixing valve, etc. and try to communicate that to us... see if we can help from there. Thanks

my water cycles hot, then cold, from the hot faucet. I at first thought it was my water heater, but I replaced the thermostat on it and cleared the water heater. When replacing the thermostat, I cut off incoming water to the water heater. I was thunderstruck when I saw that my kitchen faucet still worked, hot and cold. Please help me, it is annoying me very much!

Sounds like the cartridge in a mixing valve has gone points up -- Most likely in the kitchen sink faucet.

With the H/W tank still turned off -- Turn the hot stop off under the kitchen sink and then check to see if you still have water coming out when the handle is rotated to the hot side, if you do, then the cartridge is bad.

If you don't -- With the H/W tank still shut off, turn all of the tub/shower and lavatory single handled valves one by one to the cold side and recheck the kitchen sink faucet until you have discovered which one has failed.

Cummins... start at growler post... his has most likely scenario. I have never had this happen... but it makes perfect sense when looking at some of the cartridge assemblies they make today! Good luck and let us know what you find.

I just did it, It seems like my shower mixing valve is bad. What brands would you recommend? The shower is a two handle, with mixing valves. I called up a guy and he told me all faucets made after 2000 have mixing valves, regardless of amount of handles.

I recommend the symmons valves or the moen valves. I have yet to be really disappointed. Good luck.

I thought I heard some bad things about Moen. Do you know of any other valves that will make a tight budget?

There are some people posting that moen takes time to deliver warranty materials... not that I have seen. Most of my issues received 24 hour (overnight delivery) or less... so I will always recommend Moen.

Other good brands? Delta... American Standard, Kohler... Let us know what you decide.