How I cut down on shower warm-up water usage.

[MurphyMan]

Hi gang.

Last year we bought a 2006 Class C Outlook last year and are enjoying the heck out of it, especially in boondocking situations. Since we only carry 43 gallons of fresh water, the resource is precious. I really came to hate how much water we would waste to get hot water to the bathroom sink and shower. I'm pretty sure we would use a full gallon of water before the HW arrived at the shower head. I know some people capture this water for other purposes, but I was looking for something more elegant.

To improve the situation I decided to install a re-circulation line. I could install a 12 volt switching valve to run the water for 15 seconds or so before taking a shower, which would run back into the fresh water tank.

I used a Misol 12 volt 1/2" motorized ball valve that I got off of Amazon for 26 bucks. It came over on a slow boat from China, but that was okay.

For the port back into the fresh water tank, again from Amazon, I got a 1/2" Barbed self sealing water tank fitting for eight bucks. This gizmo allows you to attach a fitting without having to have access to the inside of the tank. Easy to install. I used a 7/8" hole saw.

The Misol valve only has two leads coming out of it, so you need a switch that will reverse the polarity. I used a double pole, single throw switch, like this. I have the S700-2-3, ON-ON switch. For the +12 volt supply, I tapped into the supply for our propane detector, with an additional 2 amp inline fuse.

I think the hardest part was running the 1/2 tubing all around. Naturally it took several trips to the RV supply place for the various fittings I needed. All in all I probably spent $75-100 bucks.

So how well does it work? I was really pleased to find the system working properly the first time I turned it on. In the up position the valve opens and water is shunted back to the fresh water tank. In the down position, the valve operates, closing the route to the tank. I have not yet operated it with hot water, as I am winterizing "Squeaky", but I have all the confidence that we will be conserving a lot.

Was it worth it, who knows? But it was an interesting project.

Edit: I almost forgot. Prior to this project I also installed a thermostatic shower temperature control as seen in this YouTube video. We really love it and it works great. As always, the installation is harder than it seems at first glance. Allow plenty of time to get these done.

[cptdzl]

Sure beats running the water into small containers to save for later flushing. does the ball valve require power in both positions, what kind of current draw in the normal position (non recirculating)

Thanks for the write up.

[MurphyMan]

Originally Posted by cptdzl

Sure beats running the water into small containers to save for later flushing. does the ball valve require power in both positions, what kind of current draw in the normal position (non recirculating)

Thanks for the write up.

Once the ball valve reaches it's stop it quits and doesn't draw any current. It's a motorized valve, so yes it requires power in both conditions, hence the fancy switch arrangement.

[harleyjt]

Thats a really neat mod! I like it! But its a bit more involved than I think I want to get into.
jt

[Easyrider]

Great idea that many of us can use!

[Snowman9000]

Very nice, I like it. Do you drink your onboard water? If so, will the taste be altered by this little bit going through the water heater?

There are systems to do this in houses, but I don't know where they route the return water back into the system.

[bargeman]

Nice mod... why a motorized valve instead of a solenoid valve?

[nosticks]

Thanks for the parts list. I have though about doing this, now you have simplified it to the point of a winter project.

[MurphyMan]

Originally Posted by Snowman9000

Very nice, I like it. Do you drink your onboard water? If so, will the taste be altered by this little bit going through the water heater?

There are systems to do this in houses, but I don't know where they route the return water back into the system.

Good question, I didn't think of that but we'll have to wait and see. We winterized and put it into storage until after Christmas then we'll hit the road. We do have a charcoal filter for the kitchen faucet.

[MurphyMan]

Originally Posted by nosticks

Thanks for the parts list. I have though about doing this, now you have simplified it to the point of a winter project.

Other than waiting for two and a half weeks for the valve to show up, my biggest hassle was getting the fittings. Our RV supply house is about 20 miles away, so I made three or four trips there by the time it was done. With better planning I wouldn't have made so many trips, but that's me.

I did have an electrician's cheap fish tape around the house and that helped a lot for pulling the half inch tube through the small spots.

[MurphyMan]

Originally Posted by bargeman

Nice mod... why a motorized valve instead of a solenoid valve?

Motorized valve was the only one that I can find in a 12-volt that seems suitable. It's kind of funny it takes about 3 seconds for it to operate.

[Hikerdogs]

Originally Posted by Snowman9000

Very nice, I like it. Do you drink your onboard water? If so, will the taste be altered by this little bit going through the water heater?

There are systems to do this in houses, but I don't know where they route the return water back into the system.

When we built our current house the plumber was trying to talk us into a recirculating system for the kitchen sink. Mainly because there's a good 100 feet of plumbing between the sink and the water heater. The system consisted of a return line from the hot supply side back to the bottom of the water heater. In this case the water the water would set up a convection current with the warmer water rising and the cooler returning to the heater. There were no valves or switches involved just a continuous flow. The cost at the time (1987) was over $500.00. At that time $500.00 sounded like a lot more money than it does today. Unfortunately we passed on the proposal.

Nearly 30 years later it's something we wish we had, but at the 1987 prices not today's prices.

I must say I do like MurphyMan's resolution to the problem. Not overly expensive and no cold blast of water to wake you up in the morning.

[Isaac-1]

Good idea, I think I am going to try adding something like this

[4x4van]

Fantastic!!! We just returned from our first boondocking trip in our new (to us) 30' class A, and have the same issue. My coach could not be set up any worse for getting hot water to the tap.

My water heater is up in the right front corner, just behind the front tire. From there, the lines go all the way back to about 3' behind the rear axle, cross to the other side, and then forward to about halfway between front & rear axles. From there, they STILL have to go through a large loop, since the kitchen is in the slideout! Based on Winnebago's plumbing schematics, I have 41.5 feet of line from the water heater to the tap!!!! Assuming a 1/2' diameter line, that is 1.7 gallons wasted before the hot water ever reaches the kitchen faucet!!!! Ridiculous!

My thoughts on the way home were exactly what you did, except I was thinking of a manual valve just under the sink (in the cabinet). But I like your idea of the electrically operated valve better; it allows a cleaner install and more easily accessible switch. It would also allow a second switch in the bathroom for the same valve/purpose!

Thank you, Thank you, Thank you!!!

[Jim_HiTek]

NICE! As an electronics designer, my brain immediately turned to the possibility that you could have a circuit timer that you'd push a button and it would turn on the valve for 15 (adjustable) seconds, then turn it off.

Fun, and a great project.

Well done!

[bodycoach2]

RV Grey Water Recycling - Unique Solutions Inc RV has a hot water recirculator. They also make a grey water toilet flush system. Both together would save a LOT of water in our RV. Putting low flow fittings on sinks will help too.

[Isaac-1]

Originally Posted by Jim_HiTek

NICE! As an electronics designer, my brain immediately turned to the possibility that you could have a circuit timer that you'd push a button and it would turn on the valve for 15 (adjustable) seconds, then turn it off.

Fun, and a great project.

Well done!

I had a similar idea, there are cheap 555 timer based variable delay relays available on ebay for under $10 (most are 0-10 seconds, but some are 0-20 or 0-60), combine this with a small 12V solenoid valve with a bit of plumbing and a momentary contact button and you get a one click solution. Sure a 555 is not a precise timing system as accuracy of the timing circuit varies with ambient temperature, but +/- a second or so at 20 seconds should be close enough for this sort of application.

[S Bradley]

I liked your conversion to the mixer valve, finish looked great.
Good ideas.

Thinking about your last project did you consider:
Using the water fill line to return your water to the water tank, rather than punching another hole in the tank?
How about creating a loop back to the water heater instead of the water tank?
After doing the install how many fittings do you think you could remove from the project using pex tubing.
Why not use a manual ball valve? I'm a keep it simple person and adding electrical anything to a motor home is a potential trouble.

Solenoid is a good idea but still requires power.

[MurphyMan]

Originally Posted by 4x4van

Fantastic!!! We just returned from our first boondocking trip in our new (to us) 30' class A, and have the same issue. My coach could not be set up any worse for getting hot water to the tap.

My water heater is up in the right front corner, just behind the front tire. From there, the lines go all the way back to about 3' behind the rear axle, cross to the other side, and then forward to about halfway between front & rear axles. From there, they STILL have to go through a large loop, since the kitchen is in the slideout! Based on Winnebago's plumbing schematics, I have 41.5 feet of line from the water heater to the tap!!!! Assuming a 1/2' diameter line, that is 1.7 gallons wasted before the hot water ever reaches the kitchen faucet!!!! Ridiculous!

My thoughts on the way home were exactly what you did, except I was thinking of a manual valve just under the sink (in the cabinet). But I like your idea of the electrically operated valve better; it allows a cleaner install and more easily accessible switch. It would also allow a second switch in the bathroom for the same valve/purpose!

Thank you, Thank you, Thank you!!!

Sounds like you really have a need for this type of a setup. In my RV I have about 25 feet from the water heater to the bathroom sink. Not quite that much to the shower.

I didn't want a manual valve because I didn't want my wife to have to open a cabin or something to operate it. This way she can just throw the switch. Admittedly, some sort of a circuit timer would be nice but that made my project more complicated than I was interested in tackling.

[MurphyMan]

Originally Posted by S Bradley

I liked your conversion to the mixer valve, finish looked great.
Good ideas.

Thinking about your last project did you consider:
Using the water fill line to return your water to the water tank, rather than punching another hole in the tank?
How about creating a loop back to the water heater instead of the water tank?
After doing the install how many fittings do you think you could remove from the project using pex tubing.
Why not use a manual ball valve? I'm a keep it simple person and adding electrical anything to a motor home is a potential trouble.

Solenoid is a good idea but still requires power.

It was the simplest and easiest just to put another hole in the freshwater tank. It it may be easier to install it in the fill line in other RVs.

Sending the water back to the water heater didn't seem to make any sense at least as far as my RV is concerned.

I think I used six fittings not including the one that goes into the tank.

If I used a manual ball valve it would have had to the inside of a cabinet as I wouldn't want to have it to have to look at it. Then if it was inside the cabinet it probably wouldn't get used very often. I just put the switch in a fairly unobtrusive place underneath the medicine cabinet.