Freshwater is hot(?)

[Just Me-FRF]

I have a 2017 Greyhawk 26Y. We had taken it on a 5 hour trip to see the total solar eclipse (the eclipse was awesome!) and when my daughter tried to shower after we got back to our campsite (about 2 hour drive from where we actually viewed the eclipse) she indicated that she couldn't because the water was too hot.

My daughter can be a little 'dramatic' at times and we have had varying levels of issues with our tankless water heater (that's a whole other story). I told her that if the water was too hot, to shower with cold water then. (I was being a bit of a smart a..leck as I was tired from driving and was wanting to relax at camp (not mess around with the hot water heater).

My daughter replied that she *had* tried to shower using only cold water and the water was too hot. Frankly, I didn't fully believe her. So I marched into the shower and turned only the cold water on, and sure enough the water was too hot to hold my hand under for more than a few seconds. I turned off the hot water heater (even though I was only running cold water) and ran all the cold water faucets for a few minutes. All were pumping out hot water. Too hot to even shower comfortably with.

It had been about 92 degrees that day, but this water was way hotter than that.

I had city water at the campsite, and I had filled the freshwater tank prior to our 2 hour excursion from the campsite to the solar eclipse and since we were leaving the next morning I had not planned on hooking up to city water again). I went out to the freshwater tank low point drain and opened the drain. Hot water came out! Somehow (it seems) my freshwater tank water was being heated.

I hooked up to city water and all showered without any further incident that day and I let the hot water drain out of the freshwater tank. Prior to leaving the next morning, I filled the freshwater tank about 1/3 full for the trip back home. I dumped the tanks and re-charged the toiled so we could have the use of facilities at that time. I checked the water temp at that time and it was cool (as one would expect). On our way home when stopping at a rest area,I noted the water was hot again. We had been driving for about 2 hours at this point. I measured the water temperature with a thermometer I had gotten from a Love's store to measure liquid temperatures. The water temperature was 118 degrees and the outside temperature was much cooler than the previous day (77 degrees). I wasn't sure where the freshwater tank was located so I checked all the tire pressures just to make sure I didn't have a heat situation from a tire that was contributing to this issue. Pressures were where they should have been and there was no excessive heat from the tires.

When I got home (about three hours later) I checked the water temp directly from the freshwater low point drain and the water was 122 degrees!

Anyone have any ideas what the problem might be? My best guess is heat from the engine, but the engine was at normal operating temperature (I was driving in Southern Illinois and Kentucky so there are no significant hills to speak of that would tax the engine). If it is the engine, shouldn't there be a "shield" or something that insulates the tank from the heat?

BTW - I did confirm the tank heaters were off during all of this issue (at least the switch was off). Could a short be the issue?

The only thing against that theory is that I plugged in the camper when I got home and it got down into the low 60s last night. When I checked the water this morning it was about 89 degrees, so it is cooling. If the tank heaters were causing the problem, I would think I would still have hot water in the freshwater tank. (Plus I believe the tank heaters are for the grey and black water tanks (not freshwater) but I could be mistaken on that)

Totally baffled by this. Ideas/Suggestions are welcome...

 

[rodro123]

The valve on your water heater is flipped the wrong way. Currently you are back filling your fresh water tank with hot water.

 

[Just Me-FRF]

If that's true, why wasn't the tank full of hot water prior to my departure yesterday? I filled it 1/3 full before leaving the campground, and the low point water drain (as well as the interior faucets) were bringing forth cold water at that time. It wasn't until I had driven about 2 hours that I checked again and found the hot water. (Also I have an on demand WH - FYI)

 

[LkptRvPilot]

A few years back, we took a trip to Florida in November. I remember it wasn't a super hot day, maybe in the 80's, but the sun was bright and the road asphalt was just burning. Getting out at a rest stop, the ground was very hot. It was exactly at this time when I noticed the "cold" water was hot. I don't know about 122 degrees, but it was hot when washing hands, ect.

I wouldn't write it off yet and keep it in the back of your mind, but it could simple be from the hot road.

 

[Just Me-FRF]

Thanks for the suggestion. I kind of thought it might be that on the day of the eclipse since it was pretty hot (low 90s) and it could be that it was the pavement. But...when I started out on the day after, I had a "fresh tank" of cold water from the campground and the temps were in the mid to upper 70s with sporadic rain so I wouldn't think the pavement was that hot. (But I could be wrong). It just doesn't seem to make sense.

 

[pconroy]

On our Greyhawk we have the same thing. Our freshwater tank is below and exposed to the elements. On a hot day, with a hot road, the fresh water tank gets too hot to tolerate.

Running the hot water in the shower made it too hot to stand.

I've concluded its simply because the outside temps can heat up the fresh water tank. It only affects us a couple of trips a year. But if it becomes a problem, I've thought about trying to spray on some insulation.

 

[pconroy]

But...when I started out on the day after, I had a "fresh tank" of cold water from the campground and the temps were in the mid to upper 70s with sporadic rain so I wouldn't think the pavement was that hot. (But I could be wrong). It just doesn't seem to make sense.

Agreed - that seems odd.
Try it again, and see if you can keep tabs on the outside temps.

AFAIK, the tank heaters won't heat a 55 gallon tank to over 100*. And, I can't come up with any other explanation. If the water heater was some how involved, you'd know it by hearing it and by the propane consumption.


It seems to be tied to outside and road temps, in our case.

 

[klspahr-THOR]

We were in Nashville from Thursday to Tuesday, the motorhome was parked and everything but the fridge was turned off - my water was hot too! We stayed in my sister's house. Never seen that in our our class c (water tanks were inside on that one).

I think it was either the total eclipse alien's ray guns or maybe the 96+ degrees everyday we were there.

Nice to hear this happened to more than just us - so I wasn't going crazy. The total eclipse aliens said I was.

 

[GScott423]

We had the same thing happened in the hot Arizona sun. My wife thought we had the wires crossed and was getting hot water out of the cold faucet. My good buddy explained that the hose from the hydrant to the trailer was simply a solar collector and was getting solar hot water . He said whenever they win on National Guard training exercises the first thing they did was lay out several hundred feet of black hose so by the end of the day they had water for showers

 

[memphis02]

Does your exhaust run anywhere near the tank? Exhaust temps will easily run 400+ degrees. Otherwise, I would suggest disabling your water heater or shutting off propane and testing to rule it out.