Originally Posted by TURBS
I can't wrap my head around how this is possible.
I agree. Strange!
The only possibility I could think of is if the OP was somewhere where the weather was VERY warm and the city water hose (and possibly the pedestal hook-up) was in direct contact with the sun for a long period of time and when the cold faucet was opened it would draw that very warm water into the RV and out the faucet. Of course it wouldn't last all that long and in reality hot should come out the hot side as well, not cold so I'm stumped.
Even if the CW supply was somehow plumbed into the hot water side of the plumbing I can't imagine how it would reverse the flow at EVERY faucet?
If something was amiss with the WH bypass valves it wouldn't work correctly with the pump.