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Manual water tank heater hose: see update in first post

profdant139
Explorer II
Explorer II
(Update -- this simple device really works in the real world. We just spent a week in Yosemite where it did not get above freezing for four days in a row -- and the water lines did not freeze! It was in the teens every night. We ran the recirculating hose once in the afternoon, once in the evening, once before bed, once in the middle of the night, and once in the morning. We had plenty of propane, and the pump did not come close to draining the battery -- using our 120 watt solar panel, the battery never dropped below 12.4 volts at any time. We also ran our Honda 2000 generator for 90 minutes one afternoon, something we have not done in several years.

A few tips -- when you set up your hose, make sure that whenever you disconnect it from the faucet, gravity will completely drain the hose into the fill pipe -- otherwise the hose will freeze. And make sure that there is a swivel on the attachment between the hose and the faucet -- it makes it easier to hook the hose up and to detach it.

Bottom line -- if you have an outdoor shower door, this crude method really works if you do a few days of winter camping. If you do a lot of winter camping, a more sophisticated automatic recirculating mechanism would be preferable. And now, back to the original posting!)



During our last trip to Sequoia, the outlet hose leading from the water tank to the pump froze one night, when the temp got down to 11 degrees. After some helpful discussions on this forum, I rigged up this simple solution:

A hose connects to the water faucet. The hose runs to the outside through the outdoor shower opening. The hose runs along the outside wall of the trailer, and the end goes into the external fill pipe of the water tank. Right before bedtime, we run a few gallons of hot water, and the temp of the tank is substantially increased. The warmed-up water runs through the outlet hose and back to the pump.

This solution is so simple, crude, and obvious that I am almost ashamed to post pictures of it -- but here we go anyway. This is the end that screws onto the faucet โ€“ I have included a swivel fitting to make it easier to attach:



Here it is attached to the faucet:



The hose runs over the edge of the sink, under the counter, and into the opening for the outdoor shower:



This is a view of the hose as it passes through the outdoor shower opening:



(The word "hot" was written by whoever installed the outdoor shower at the factory.)

This is an exterior view, showing the hose emerging from the outdoor shower opening โ€“ as you can see, I have also inserted blocks of tightly-fitting closed-cell foam blocks into the outdoor shower fixture as extra insulation:



And here is the hose going into the external fill pipe door:



For storage, the whole thing coils up and goes into an under-seat storage bin.

Some thoughts and caveats:

A thermostatically controlled built-in under-counter system would be far better. But it requires cutting into the plumbing, and some electrical work. My solution is crude but effective -- very simple and inexpensive. It does the job, especially if (like us) you rarely camp in weather below 20 degrees. (We have camped at 20 many times, with no freeze, but this last trip was just a little too cold.)

Obviously, this solution only works if you have an outside shower fixture -- otherwise, how would you get the hose through the wall? And it is much easier if you have previously removed all of the outdoor shower plumbing fixtures. (We did that when we got the trailer, because it is always too cold for a late afternoon outside shower when we are boondocking. We needed the extra room under the sink more than we needed the shower, since we use the inside shower.)

The main drawback to this system is that it has to be set up whenever you want to use it and then taken down whenever you want to change your campsite. But we so rarely encounter temperatures below 20 that this will be an infrequent event.

The other drawback is that this system does not operate automatically, unlike thermostatically controlled hot water recirculators. So, for example, I plan on running this device at least once during the night, which will mean that when I get up at 3 am (which I always do), I will have to stand there for three minutes while the hot water runs into the fresh water tank. Not a deal-breaker, but not effortless, either. And the water heater will need to stay on during the entire night, which means that it will cycle on and off every few hours, which is a little noisy. Better than frozen pipes, though!
2012 Fun Finder X-139 "Boondock Style" (axle-flipped and extra insulation)
2013 Toyota Tacoma Off-Road (semi-beefy tires and components)
Our trips -- pix and text
About our trailer
"A journey of a thousand miles begins with a single list."
48 REPLIES 48

westend
Explorer
Explorer
Bobbo wrote:
westend wrote:
I would bet that if you put a hose and valve on the water heater drain, the same thing could be accomplished.

But that would involve him having to go outside to run the water. He doesn't want to do that. His current setup lets him run the water from the kitchen faucet.
Not if the valve is turned to a position where it isn't full flow. I envisioned opening the valve, initially, to full flow to add a lot of hot water and then necking it down to a mere trickle. The downside is that the pump would occasionally run because of the small amount of heated water displaced but this would be "hands off" if set up correctly. Full manual operation could be done with an electrically operated valve.

This would be a connection to the water heater drain, not to the pressure relief valve.

If I was doing this type of system, I'd just tap into the RV's plumbing lines and forget about any exterior hoses or connecting to the kitchen sink. There's lots of ways to skin this cat.
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profdant139
Explorer II
Explorer II
And I don't want to interfere with the relief valve. It has never popped, but there is always a first time. Safety is more important than anything else.
2012 Fun Finder X-139 "Boondock Style" (axle-flipped and extra insulation)
2013 Toyota Tacoma Off-Road (semi-beefy tires and components)
Our trips -- pix and text
About our trailer
"A journey of a thousand miles begins with a single list."

Bobbo
Explorer II
Explorer II
westend wrote:
I would bet that if you put a hose and valve on the water heater drain, the same thing could be accomplished.

But that would involve him having to go outside to run the water. He doesn't want to do that. His current setup lets him run the water from the kitchen faucet.
Bobbo and Lin
2017 F-150 XLT 4x4 SuperCab w/Max Tow Package 3.5l EcoBoost V6
2017 Airstream Flying Cloud 23FB

westend
Explorer
Explorer
I would bet that if you put a hose and valve on the water heater drain, the same thing could be accomplished. The pump would run as the hot water is demanded from the drain outlet but this would fill the fresh tank and, eventually, the whole system with heated water, if a user drained off some of the existing cooler water in the cold water supply piping.
'03 F-250 4x4 CC
'71 Starcraft Wanderstar -- The Cowboy/Hilton

profdant139
Explorer II
Explorer II
Unfortunately, Salvo, I get up at 3 am no matter what -- when you reach your early 60s, you will see what I mean. So as long as I am up, might as well run some hot water, right?
2012 Fun Finder X-139 "Boondock Style" (axle-flipped and extra insulation)
2013 Toyota Tacoma Off-Road (semi-beefy tires and components)
Our trips -- pix and text
About our trailer
"A journey of a thousand miles begins with a single list."

Salvo
Explorer
Explorer
Say, this is a great science project! We got thermal mass, thermal resistance, heat energy and all that good stuff.

I'm not sure if you actually need to get up at 3 am to run another hot water circulation. It all depends on the thermal resistance of the tank. Here's where a little more testing comes into play. We need some temperature measurements through the night (or some of it). Measure water tank and outside temperature over time. Run test with tank 1/2 full. This is where automated temperature data gathering comes in handy.

Stars101
Explorer
Explorer
My fresh water tank has a fill spout on the top, you fill it from the inside. There is no "outside" fill. And since we added the larger port (5" vs. 1.5") you can either pour a bucket directly into the tank, or even extend the shower hose and put the hose right in the fresh tank.

I like being able to pour from a pitcher, or bucket, instead of needing a funnel to use the 1.5",original fill port on top of the tank.

I'm mostly worried about the water pump... so if I run some hot water into the tank, then run some water in the shower, I should have both the pump and fresh tank safe. Or at least that's my reasoning.

The 5" marine port I added to the tank is really slick. I can fit my entire hand down in there and wipe out 99% of the inside of the fresh water tank with a bleach solution. And I can protect my low point drain by merely plugging the outlet hole from the inside of the tank with my finger, then having my DH open the low point drain to get that 1 teaspoon water that might be in it, out.

Anyway, thanks for the info. I had always wondered if anyone else thought about mixing hot water in their tank to help out with occasional winter-freeze issues. All the traditional winter fixes, i.e. heat pads, heat tape, extra-recirculating plumbing, while totally valid, seem pretty excessive for only needing it 3-4 nights the entire year - spaced over 3-4 trips.

pianotuna
Nomad III
Nomad III
Hi,

Keep it as full as you can.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

profdant139
Explorer II
Explorer II
Stars, how are you going to get the hose from your hot water faucet to the tank fill pipe -- do you have a little outside shower door, like I do? I can't figure out how I would do this trick without the outside shower door, other than rigging up a permanently-plumbed bypass valve.

Anyway, I have been fooling around with my new hose setup, hoping to do some cold weather camping. I was measuring the temp of the water in the fresh water tank before and after I added the hot water. Not surprisingly, the lower the water level in the fresh water tank, the greater the increase in temp.

So does that mean I should keep the tank half empty, in order to maximize the boost from the hot water? Or should I keep it full, in order to increase the "thermal mass" of the full tank? Probably the latter. And I will run the hot water into the tank in the early evening and just before bed (to bump up the temp), and at least once in the middle of the night, to try to keep the whole thing above freezing.
2012 Fun Finder X-139 "Boondock Style" (axle-flipped and extra insulation)
2013 Toyota Tacoma Off-Road (semi-beefy tires and components)
Our trips -- pix and text
About our trailer
"A journey of a thousand miles begins with a single list."

Stars101
Explorer
Explorer
Thanks for the info. I have a TC, so my 9 gallon fresh water tank is under the front 'step" area. We added a port so that we could reach in and clean it out. The junk they left in there from installing it was nasty; wood shavings, metal saving and plastic shavings!

Anyway, using your method I can run my hot water heater and collect the warm water and add it right back into the tank. I think I might spend a night in January monitoring the temps and playing around with it in my backyard... best place to test new theories!

I'd LOVE to be able to use the shower during winter camping. Currently we don't use the freshwater system, and the toilet is a port potty anyway.

paddywanpeep
Explorer
Explorer
Correct, the hotter water will freeze before the cooler water, we did this in chemistry class. The reason we were told is because the reaction of the hot water is cooling down very rapidly, more so then the colder water, this rapid cool down continues and surpasses the colder water so it does freeze first.

Another way to look at it is, we have all seen the videos in winter time of when its very cold out and folks will take boiling water and throw it into the air and it becomes 'snow'. The water has to be be boiling and the quick reaction freezes it. If you were to do this with just regular water it would do nothing.

There is no magic voodoo here, it is just chemistry at work.

austinjenna
Explorer
Explorer
austinjenna wrote:

Quote:

austinjenna wrote:

Doesn't hot water freeze faster then cold water? Thats what I was always told


No. You need better references.


Maybe you should read. Link

Maybe you should create a link that works. Or explain how a jug of, say, 70*F water can freeze sooner than a jug of 40*F water under the same external temperature conditions. That would be an interesting trick; if it worked then maybe we could postpone freezing by adding ice cubes.


Sorry about the link not working. I guess if you really wanted to know you could do this thing called google. Its called the 'Mpemba Effect'

2010 F350 CC Lariat 4x4 Short Bed
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time2roll
Nomad
Nomad
rexlion wrote:
austinjenna wrote:
austinjenna wrote:
Doesn't hot water freeze faster then cold water? Thats what I was always told
No. You need better references.
Maybe you should read. Link
Maybe you should create a link that works. Or explain how a jug of, say, 70*F water can freeze sooner than a jug of 40*F water under the same external temperature conditions. That would be an interesting trick; if it worked then maybe we could postpone freezing by adding ice cubes.


https://en.wikipedia.org/wiki/Mpemba_effect

All I see is that the cooler water appears to be more prone to supercooling and so can remain liquid longer. Not really going to apply to a holding tank.

Add the warm water and sleep well.

SteveAE
Explorer
Explorer
profdant139 wrote:
if my water tank is really cold and about to freeze, it can't hurt to add some hot water, right?


Right. Correct. Absolutely.

profdant139
Explorer II
Explorer II
I'm not going to get in the middle of this dispute -- I have seen it before. But all I know is that if my water tank is really cold and about to freeze, it can't hurt to add some hot water, right? If that is not true, and I should add ice cubes to the tank to keep it from freezing, I am out of luck -- ice cubes won't fit into the fill tube. ๐Ÿ˜‰
2012 Fun Finder X-139 "Boondock Style" (axle-flipped and extra insulation)
2013 Toyota Tacoma Off-Road (semi-beefy tires and components)
Our trips -- pix and text
About our trailer
"A journey of a thousand miles begins with a single list."