Cold water mixing with hot water?

If it is not the bypass valve check the outside shower

have you ever used the outside shower????

(OR in many cases the indoor shower)

Many times when we get complaints like yours it is found that the outside (or less often the inside) shower was used and the cut off in the shower head was shut off but the mixing valves were left OPEN. Closing the mixing valves fixes the problem.

yes, we've used the outside shower, and the knobs are shut off. It was doing this before I even hooked up the hose to the outside shower to rinse off the grandkids coming back from the beach.

You mention it being your first trip this season - is it new? If it isn't the outside shower or the winterizing bypass valve, the only other thing I can think of is construction debris. We had a problem with our coach back in 2007 when it was new, that a small piece of debris had gotten into a line and then broke free about two months after we bought the coach. Once we cleared the line, then it was fine.

2chiefsRus wrote:
You mention it being your first trip this season - is it new?

Is it fair to assume that you have had the unit for a while and this is a new problem ?

Also, were any major changes/repairs done to the plumbing lately ?

My first two thoughts are:
Defective valve in a single handle faucet.
Pipes to hot water heater connected backwards.
But neither of those may apply.

Does the problem occur at ALL faucets/showers ??

Edit: And how about a big air bubble in the hot water tank; is there a "bleeder" valve ?

Double-check the winterizing valves for the water heater.

Some bypass valve setups rely on one-way valves, which may be built into the water heater connections, and sometimes these one-way valves get stuck or have some debris lodged in them. Typically the one-way valve would be at the hot water output, and even if it were stuck I don't think you'd get unwanted hot and cold mixing if the other valves were set properly, but there may be some other arrangement I'm not aware of or thinking of at the moment.

Is the water heater a "10 gallon" model that actually has a six gallon tank that is heated extra hot and mixes the water at the output to get a reasonable hot water temperature? If so, that mixing valve could be acting up for whatever reason.

I've had the unit new since 11'. First time I've had this issue. I had someone look at it while it's at the campground, and he narrowed it down to the cold water bypass valve. So I have one on order. I appreciate all the help. I will now know to go here first.
Thanks again.

Rheo1

Please tell us the make/model of your water heater.

Some of the higher end Atwood hot water heaters heat the water to 180 deg. and mix that 180 deg. water with cold water via a mixing valve on the rear of the HWH. Their is also a winterize valve on the back of the hot water heater. This mixing vale can stick giving you either scalding hot water,lukewarm or cold.

Also..... remove ALL airators (spelling?) on each faucet and/or spraw wands. I was amazed at the amount of garbage that collects behind them. Put them back on when cleaned. They help save water.

mchero wrote:
Rheo1

Please tell us the make/model of your water heater.

Some of the higher end Atwood hot water heaters heat the water to 180 deg. and mix that 180 deg. water with cold water via a mixing valve on the rear of the HWH. Their is also a winterize valve on the back of the hot water heater. This mixing vale can stick giving you either scalding hot water,lukewarm or cold.
Clarification:
Atwood XT models use Mixing Valve.
Normal t-stat preset for 160*F (vs 140*F for regular models) ECO (High temp t-stat) preset for 180*F and Mixing valve output preset for 130*F

Also..... remove ALL airators (spelling?) on each faucet and/or spraw wands. I was amazed at the amount of garbage that collects behind them. Put them back on when cleaned. They help save water.

XT Models with Mixing Valves have an issue with clogging up and then only having cold water going into hot water line.

Seems you have IDd problem being with bypass valve allowing cold water to flow into hot water line. IF that is true then you must have only a check valve in hot outlet that is going closed otherwise you would have warm 'hot' water vs cold 'hot' water.

Sometimes valve handle moves but valve doesn't......handle just slips on valve stem. Remove handle and turn stem with pliers.