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Hot Water Recirculation Loop - Save Water - Camp Longer

Camper_Jeff___K
Traveler
Traveler
A Great Truck Camper / RV Modification
How to Install A Hot Water Recirculation Loop Or Recovery Loop
Save Fresh Water And Extend Your Camping Trip A Day Or Two With Water Saved By Not Running It Down The Drain While Waiting For Hot Water To Arrive At The Faucet
VIDEO Hot Water Recirculation Loop VIDEO


Valve and switch

Return Loop into Fresh tank

Return Loop from kitchen sink Hot, to solenoid valve then back into fresh tank.
28 REPLIES 28

Camper_Jeff___K
Traveler
Traveler
Dave D. wrote:
Camper_Jeff_&_Kelli wrote:
The pump would only need to run a total of maybe 40 seconds total a day pressing the switch, 6 seconds per use. Not much power.

True enough. But if I'm going to go to the trouble of plumbing in a hot water loop, I don't want to wait at all. Besides, our Host camper takes at least twice that time to get hot water to the kitchen sink.


I'd like to see how you do it. A Grundfoss Pump is big, heavy, and reliable. You might have a different pump solution. Keep us in the loop. A little plumbing joke there...

Dave_D_
Explorer
Explorer
Camper_Jeff_&_Kelli wrote:
The pump would only need to run a total of maybe 40 seconds total a day pressing the switch, 6 seconds per use. Not much power.

True enough. But if I'm going to go to the trouble of plumbing in a hot water loop, I don't want to wait at all. Besides, our Host camper takes at least twice that time to get hot water to the kitchen sink.
2020 Host Cascade, 2020 Chevy 3500

Camper_Jeff___K
Traveler
Traveler
Dave D. wrote:
Camper_Jeff_&_Kelli wrote:
That works great in a residential application but in the RV, I only want the pump to run when needed, not constantly. Battery conservation. I only need 6 seconds of run time on the pump to get hot to the sink. A residential setup has a recirculating pump that runs all the time, at preset times on timer, or at a set temperature. Typically, the loop is taken from the last fixture in line and so should the return line in this setup. My pipes are all insulated and have 1" foamboard plus the TC wall insulating them from the outside in cold temperatures. The pipes are also run together with insulation tube over them and the heater vent hose next to them. The pipes are pretty well protected from freezing.

But a recirculating pump takes little amperage compared to the pressure pump. The pressure pump would see no difference in usage -- in fact, less, as it would not have the extra duty of pumping cold water out of the lines. We are skiers, and in the RV lot can often see
zero-degree temps for a day or two at a time. Keeping water flowing at those temps requires a space heater in our camper's basement, which draws a lot more than a recirculating pump. Since we have plug-in power up there, a few more ticks isn't an issue.


The pump would only need to run a total of maybe 40 seconds total a day pressing the switch, 6 seconds per use. Not much power.

JRscooby
Explorer
Explorer
Grit dog wrote:
Well, I stand corrected scooby. Guess I never considered the wastefulness of $.30-$.60 per month of residential water bill charges.


Well maybe life experience have taught as different values. First time in my life that I could know water would come every time when I turned the knob was in the barracks. And even now, some parts of the country the water is tested to be sure it will not make you sick, but that does not mean it tastes good.

Dave_D_
Explorer
Explorer
Camper_Jeff_&_Kelli wrote:
That works great in a residential application but in the RV, I only want the pump to run when needed, not constantly. Battery conservation. I only need 6 seconds of run time on the pump to get hot to the sink. A residential setup has a recirculating pump that runs all the time, at preset times on timer, or at a set temperature. Typically, the loop is taken from the last fixture in line and so should the return line in this setup. My pipes are all insulated and have 1" foamboard plus the TC wall insulating them from the outside in cold temperatures. The pipes are also run together with insulation tube over them and the heater vent hose next to them. The pipes are pretty well protected from freezing.

But a recirculating pump takes little amperage compared to the pressure pump. The pressure pump would see no difference in usage -- in fact, less, as it would not have the extra duty of pumping cold water out of the lines. We are skiers, and in the RV lot can often see
zero-degree temps for a day or two at a time. Keeping water flowing at those temps requires a space heater in our camper's basement, which draws a lot more than a recirculating pump. Since we have plug-in power up there, a few more ticks isn't an issue.
2020 Host Cascade, 2020 Chevy 3500

Camper_Jeff___K
Traveler
Traveler
Dave D. wrote:
Just watched the video, now I get what is meant by the OP's use of the term "recirculating." He is describing recycling cold water back to the main tank. To me, I was thinking "instant on" recirculating hot water, which creates a loop from and back to the hot water tank, which is driven by a recirculating pump, different than the main pressure pump. This loop is always heated, and when a hot water fixture is used the pressure drop in the loop turns on the main pump which actually provides the driving force for water to come out of the faucet.

This would keep the hot water from freezing; the back-to-main-tank loop would not. With properly insulated lines it should not pull too much extra duty from the hot water tank. This is how it works in my house -- even in rooms farthest away from my boiler/hot water tank I have hot water right away.


That works great in a residential application but in the RV, I only want the pump to run when needed, not constantly. Battery conservation. I only need 6 seconds of run time on the pump to get hot to the sink. A residential setup has a recirculating pump that runs all the time, at preset times on timer, or at a set temperature. Typically, the loop is taken from the last fixture in line and so should the return line in this setup. My pipes are all insulated and have 1" foamboard plus the TC wall insulating them from the outside in cold temperatures. The pipes are also run together with insulation tube over them and the heater vent hose next to them. The pipes are pretty well protected from freezing.

Camper_Jeff___K
Traveler
Traveler
joshuajim wrote:
First, I have installed a recirculation/conserving system in my campers since 1995.
Second, the water should return to the cold holding tank. If the water was hot at the faucet you don’t need to recirculate it. The reason to recirculate is to get hot water to the faucet and return the cold water in the line to the tank,
Third, I use a cheap inline irrigation valve ($10 to $12) and a $2 doorbell button. No need to go to specialty valves and pumps.


But the stainless-steel valve looks so nice, and the button has that pretty blue light when you push it. Appearance has to be worth something. Just kidding, if it works, that's all it needs to do.

Camper_Jeff___K
Traveler
Traveler
StirCrazy wrote:
Camper_Jeff_&_Kelli wrote:
StirCrazy wrote:
Camper_Jeff_&_Kelli wrote:
Dave D. wrote:
This might be useful for winter camping. Hot water won't freeze up. Although shouldn't the recirculation return to the hot water tank, not the main tank? At least this is how I plumbed my house's recirc. heat.


The water needs to return to the low pressure side of the pump to cause a pressure drop so the pump will start. Returning to the water heater has no pressure drop because it's on the pressure side of the pump so the pump won't activate because no pressuredrophappens. You could return water to the cold Input of the water heater but to make it work, you would need a small pump and a check valve to prevent backflow. Another way to connect if you can make room is to put the return connection to the pipe between the tank and the pump. This way, there is a low pressure connection to the fresh tank and the water will recirulate directly into the intake side of the pump and get pumped right back out into the system, not into the tank


neet idea but I think if I were to implement this I would not return it to the tank but rather create a loop from the hot water heater and use a small circ pump. that way you could use it even if you had water hookups but now sewer.


True, it won't work when hooked up to citi water but then it's an endless supply of water so running the water to get hot doesn't matter since water is unlimited. When hooked up to city water, I run the water anyway to get the hose smell and taste from the hose out of the line. I have a blue hose that isn't supposed to smell but it does, just not as bad as the white hose.


I thought this was about not filling the waist take up as fast. I have camped in several places that have water and power but you dump on the way out if there is a dump. ya I have both a blue and white house in the 5th wheel, the only thing I noticed about the blue one is it costs more 😉


I'm posting mostly to see how deeply imbedded this post can get. I only hook up to water if I have a sewer connection, otherwise we'll use electric if it's there but pass on just city water.

Dave_D_
Explorer
Explorer
Just watched the video, now I get what is meant by the OP's use of the term "recirculating." He is describing recycling cold water back to the main tank. To me, I was thinking "instant on" recirculating hot water, which creates a loop from and back to the hot water tank, which is driven by a recirculating pump, different than the main pressure pump. This loop is always heated, and when a hot water fixture is used the pressure drop in the loop turns on the main pump which actually provides the driving force for water to come out of the faucet.

This would keep the hot water from freezing; the back-to-main-tank loop would not. With properly insulated lines it should not pull too much extra duty from the hot water tank. This is how it works in my house -- even in rooms farthest away from my boiler/hot water tank I have hot water right away.
2020 Host Cascade, 2020 Chevy 3500

joshuajim
Explorer
Explorer
First, I have installed a recirculation/conserving system in my campers since 1995.
Second, the water should return to the cold holding tank. If the water was hot at the faucet you don’t need to recirculate it. The reason to recirculate is to get hot water to the faucet and return the cold water in the line to the tank,
Third, I use a cheap inline irrigation valve ($10 to $12) and a $2 doorbell button. No need to go to specialty valves and pumps.
RVing since 1995.

Grit_dog
Explorer III
Explorer III
Well, I stand corrected scooby. Guess I never considered the wastefulness of $.30-$.60 per month of residential water bill charges.
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold

StirCrazy
Traveler
Traveler
Camper_Jeff_&_Kelli wrote:
StirCrazy wrote:
Camper_Jeff_&_Kelli wrote:
Dave D. wrote:
This might be useful for winter camping. Hot water won't freeze up. Although shouldn't the recirculation return to the hot water tank, not the main tank? At least this is how I plumbed my house's recirc. heat.


The water needs to return to the low pressure side of the pump to cause a pressure drop so the pump will start. Returning to the water heater has no pressure drop because it's on the pressure side of the pump so the pump won't activate because no pressuredrophappens. You could return water to the cold Input of the water heater but to make it work, you would need a small pump and a check valve to prevent backflow. Another way to connect if you can make room is to put the return connection to the pipe between the tank and the pump. This way, there is a low pressure connection to the fresh tank and the water will recirulate directly into the intake side of the pump and get pumped right back out into the system, not into the tank


neet idea but I think if I were to implement this I would not return it to the tank but rather create a loop from the hot water heater and use a small circ pump. that way you could use it even if you had water hookups but now sewer.


True, it won't work when hooked up to citi water but then it's an endless supply of water so running the water to get hot doesn't matter since water is unlimited. When hooked up to city water, I run the water anyway to get the hose smell and taste from the hose out of the line. I have a blue hose that isn't supposed to smell but it does, just not as bad as the white hose.


I thought this was about not filling the waist take up as fast. I have camped in several places that have water and power but you dump on the way out if there is a dump. ya I have both a blue and white house in the 5th wheel, the only thing I noticed about the blue one is it costs more 😉
2014 F350 6.7 Platinum
2016 Cougar 330RBK
1991 Slumberqueen WS100

JRscooby
Explorer
Explorer
Camper_Jeff_&_Kelli wrote:

True, it won't work when hooked up to citi water but then it's an endless supply of water so running the water to get hot doesn't matter since water is unlimited.



This is the problem I have; Just because pipes carry it instead of you does not mean water is unlimited.

Grit dog wrote:
JRscooby wrote:

My house, built in '50s, I have a small tank heater under the kitchen sink. A timer turns it off/on so I have instant hot water when I'm most likely cooking/cleaning. Yes, the bucket is used in bathroom then flushes toilet when needed.


You're a bucket dumper in your house? Wow

Although maybe giving rise to my next question....
Why does it appear that you cannot just tell someone "Hey, looks great, bet it works well." and stop there?


My house, and I bet most in the country, I turn on water in shower, wait for heater to kick on, heated water starts to flow, get temperature adjusted, divert to shower head, there is over a gallon in the bucket.
Now this gallon was been pumped from city well, been thru the treatment plant, and pumped to my house. After it goes down the drain, it must be pumped a couple more times to get to sewage treatment plant, treated, then dumped in river.
My low-flow toilet has 2 flushes. If there is solids in the bowl, dumps about twice as much as just liquid. But if water in bucket, dump in bowl, then use the small flush, I have a clean toilet and saved that gallon of water.
I do think the OP's idea is good. The issue I have/want to point out is just like all the solar panels, and LED lights everybody talks about to reduce power use in camper, it would be better to do the mods to our homes where we could save the most power, or in this case, water.

Camper_Jeff___K
Traveler
Traveler
ticki2 wrote:
Having flushed more than one water heating tank I would not want to return from it to my fresh water tank . But that’s just me

I can guarantee you there is not much difference in internal appearance between your home hot water heater and your RV water heater. Being from Seattle, we enjoy as clean and soft water as you can get anywhere so inside the tank doesn't look too bad. I have never gotten a cup of water heater water at any sink location that looked in the least bit questionable. I have no problem drinking hot water in the shower or brushing teeth. Never had a problem with it. Even so, the amount that will find it's way back into the fresh tank is small so I'm just not worried. If it really bothers you, you can connect the return line to just between the tank and the pump. That way, tank mixing will be nearly 0 and the loop water will simply be drawn into the pump and recirculated immediately back to the water heater.

ticki2
Explorer
Explorer
Having flushed more than one water heating tank I would not want to return from it to my fresh water tank . But that’s just me
'68 Avion C-11
'02 GMC DRW D/A flatbed