Hot Water Recirculation Loop - Save Water - Camp Longer

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...

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.

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.

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.

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.

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.

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.

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.

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.

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.