Cold Water from Hot water faucets

[capeApe]

Hi guys. I have a 1995 RoadTrek popular 190 Chevy. Issue: Cold water from hot water faucets. Yes water tank heats up. Yes bypass in correct position. I am way past all that.
I am having the most peculiar hot water problem. I started diagnosing and I noticed the cold water line was going into top of hot water tank.
I fixed that by reversing the lines, and also replaced the by-pass valve kit as they were allowing water to get past the stop valve no matter what position it was in. Still no hot water from faucets. (yes bypass is in correct position)

On hot water tank, I disconnected top water line (with bypass on until I was ready), and the hot water tank was still full, and I turned on pump, and then opened bypass valve to allow hot water from tank to flow out from top valve.
I was definitely getting good flow and nice hot water from the top output. But when I connect the plumbing line, I cannot get hot water from the faucets.
HOWEVER, when the pump was turned off, there was still enough pressure in the tank from being hot to push some water out, and the water from sink faucet was HOT only with the pump off (from sink faucet) and turned instantly cold when I flicked the pump on.

It's the weirdest thing. Someone mentioned a "mixing valve", or maybe there is another check valve down the line that it not allowing more hot water through when the pump is running and the cold water is somehow overriding it? Addition: There is an end-point faucet that was installed with a very expensive in-line water filtration system

I've asked on a few facebook groups so far with no luck and it's been 10 days troubleshooting this issue! Please help!

Thanks in advance for your time.

 

[BooneDock]

New faucet? New flex water lines & red and blue plastic plugs removed?
Are the water lines reversed up at the sink, or clogged hose or screen?

 

[Kevin D Pem]

I know! I read your post!

BUT the bottom bypass valve is in the wrong position.

 

[capeApe]

I know! I read your post!

BUT the bottom bypass valve is in the wrong position.

Hi Kev. I have a B Eng and have designed systems much more difficult than 2 bypass valves ;-) I was trying different combinations as requested by another user. Here is what I found:

• there is cold water from hot water faucet with bottom bypass valve in bypass and top valve set to tank
• with bottom set to tank and top set to bypass; hot water flowed out sink faucet without pump on but turned cold with pump on

So bizarre! Originally, the cold water line was going to top of tank so I changed that to the bottom...

 

[Kevin D Pem]

Hi Kev. I have a B Eng and have designed systems much more difficult than 2 bypass valves ;-) I was trying different combinations as requested by another user. Here is what I found:

• there is cold water from hot water faucet with bottom bypass valve in bypass and top valve set to tank
• with bottom set to tank and top set to bypass; hot water flowed out sink faucet without pump on but turned cold with pump on

So bizarre! Originally, the cold water line was going to top of tank so I changed that to the bottom...

Looking at The valves, that is what I saw. That's OK, I don't have the problem!

 

[RandyB]

If you have an outside faucet, be sure that the faucet valve(s) itself is closed and not just the wand valve is closed. Same for the shower, make sure the mixing valve is in the shut-off position.

 

[capeApe]

I was able to contact previous owner. he by-passed some of the plumbing lines under the RT because the hot water faucet was leaking at the outdoor shower faucet. Would have been nice to know this before I cut the lines at the tank because I was getting water from the top line, so I reversed them, and then spent over 2 weeks troubleshooting, installing new bypass kit, etc ....