Wasting water waiting for hot water???

[Rbertalotto]

While waiting for hot water to reach the faucet, I seem to waste a lot of precious water when I'm boondocking. Has anyone installed an undersink, propane, on demand hot water heater?

Or some other way to return this unused water to the water tank?

[Rbertalotto]

Great! Thanks for getting back to us. Looks like a perfect solution.

[Leaf-Peeper]

Rbertalotto wrote:
Nicely done! This is in your Roo? What are the real life results? How long do you wait for hot water and did you see an increase in life of your fresh water reserves? Thanks

Yes, this is in our Roo. It works very well for us. The wait for hot water is probably about 3 seconds, 5 max. I had calculated (based on 1/2" line and distance from the water heater to bathroom) that about a quart of water sits waiting in the hot water line from the bathroom (rear of camper), to the water heater (very front of camper). If I recall correctly, the pump draws about 1 amp while in operation, runs about once every 20 minutes for about 30 seconds until the thermostat is satisfied. The system is tied into water heater circuit and main cabin lights. Both the water heater & lights must be switched on in order for the system to operate, this way it doesn't operate when it's not needed.

[Rbertalotto]

Nicely done! This is in your Roo? What are the real life results? How long do you wait for hot water and did you see an increase in life of your fresh water reserves? Thanks

[Leaf-Peeper]

Here's a link to some photos with notes for our hot water recirculation system. https://www.flickr.com/photos/120944857@N06/13289564183/in/photostream/

[weathershak]

All I could afford wrote:
My technique is to brush my teeth immediately before my shower, using the hot water valve at the faucet. (Not leaving it running...just as needed). This will usually kill a half gallon and purge most of the cold without waste

X2

[Big_Katuna]

We camp state parks often so have water but no sewer. I dont care about saving water but managing the grey tank.

[Dutch_12078]

At our previous two S&B's, I installed smaller water heaters at each point of use, rather than one large one when I built them. Every hot faucet had hot water within a couple of seconds at most. I'm currently determining the feasibility of adding a second 6 gallon heater under the bathroom sink in our coach. The existing heater is just a few feet from the kitchen sink, but a 10' or so pipe run from the bathroom. The second heater would be fed from the existing heater, giving us both "instant" hot water in the bathroom, as well as doubling the capacity when we have full hookups where water usage and waste capacity are not issues.

[RCMAN46]

I have a rear kitchen 5th wheel with the water heater at the very back of the trailer.

I had the undercarriage of my trailer open to do some other work.

While it was open I run a water line from the front of my 5th wheel to the rear where my water heater is.

Then I installed a small 12 volt pump similar to this one water pump at the front of the trailer.

The pump is controlled by a temperature switch and I used an ordinary water heater adjustable switch like most home electric water heaters use.

The inlet to the pump is a T connection at the hot water line as close to the end of the hot water to the front of the trailer. Just before the pump a check valve is required to prevent back flow.

The outlet of the pump goes to the cold water inlet of the water heater via the line I had previously installed and a T at the water heater.

I also installed a switch in the pump 12 volt line so I can turn the system off when not using the trailer.

Now I have almost instant hot water at the shower and sink at the front of my trailer.

If you do not want to install the extra water line you can have the pump go to the cold water at the front of the trailer. The down side is the cold water will be hot until the line is purged from the water tank. In retrospect this would not be a problem in my case as all of the water used in the front of my trailer is for washing or bathing. If the cold water is hot to warm it is not a problem. The toilet will also have hot water but that should not be a problem either.

[Big_Katuna]

We camp state parks often so have water but no sewer. I dont care about saving water but managing the grey tank.

[2oldman]

Golden_HVAC wrote:
I never worry about a few ounces of water lost while waiting on warm water.

x2. I spend my time making sure I have enough water to live comfortably.

[Lynnmor]

Simply tee into a hot water line as close to the shower as possible, under the sink may be good. Add a valve after the tee and run this line to the fresh water tank fill.

Open the valve till hot water reaches it. Close the valve. Done.

[All_I_could_aff]

My technique is to brush my teeth immediately before my shower, using the hot water valve at the faucet. (Not leaving it running...just as needed). This will usually kill a half gallon and purge most of the cold without waste

[Dusty_R]

In a stick & brick with the water heater in the basement and with kitchen and bath on main floor, you don't need a pump. All you need to do is tee into the hot water line at the farthest point from the water heater. Then run a return line from that tee to the bottom of the water heater. The water will thermosiphon back to the water heater.
Would this work in a RV ? Good question, I think it would, but not as well as it does in a home with the water heater in the basement.

[Rbertalotto]

Steve, Your design using a 555 timer is brilliant! Wish we could see a design drawing of how you actually did it. Sounds like a perfect solution.