Recirculating Hot Water

[Crash]

We are looking for a way to ensure the fresh water tank doesn’t freeze during short ski trips – a night or two. We will put RV anti-freeze in the black and grey tanks - so they should be fine.

While we have a big BestGo battery, DC heating strips use a lot of battery power. As an alternative I found this interesting post recirculating hot water in an RV that uses the water heater instead of DC heating strips.

The idea is to use the hot water heater and water pump to recirculate the hot water into the fresh water tank. Note that we don’t need the fresh water to drink or cook – the focus is on being able to take a hot shower after a day or two of skiing.

This is simple in operation: you tap into the hot water line and put it through a ball valve. When the valve is open, hot water pours into the fresh water tank. The ball value is NC and opens using a mechanical temperature switch. Power comes from the 12 V circuit that powers the water pump with an additional rocker switch to disable the recirculation. A diagram is attached below.

To implement this, I would need to put a Y into the fresh water fill pipe. I don’t recognize the kind of flexible pipe that Escape uses for the fresh fill line; anyone have a pointer?

Would it be easy to put in a T or Y junction? Guessing I might need to 3D print a nylon Y connector with openings for the existing line in, hot water in, and capillary tube.

Any other concerns or suggestions on doing this?

[huskersteffy]

You may not have to run any wires to the existing pump. Once your "Normally Closed" valve opens via your temperature switch, the pump will kick on as it detects a loss of pressure.

Also, you may want to consider using a single point temperature sensor mounted in a corner of the fresh water tank (may have to drill hole unfortunately), since a capillary type sensor kind of averages the temperature along its length. The way you things sketched out, the sensor will immediately detect the hot water coming from the heater and then shut things off.

[Centex]

Originally Posted by Crash

.... To implement this, I would need to put a Y into the fresh water fill pipe. I don’t recognize the kind of flexible pipe that Escape uses for the fresh fill line; anyone have a pointer?

Would it be easy to put in a T or Y junction? Guessing I might need to 3D print a nylon Y connector with openings for the existing line in, hot water in, and capillary tube. ....

You might want to see this post https://www.escapeforum.org/forums/f...tml#post404150

In that post alanmalk describes a similar mod he had installed by ETI long ago, but routing the recirculation via the freshwater vent tube rather than the fill pipe. The vent tube, being a smaller smooth type may be easier to match with a Tee fitting.

Just for your consideration, Have Fun!

[kstock11]

An alternative is to use the winterizing valve and draw from a water container (I use a 6 gallon) that I place near the water pump. I leave the fresh water tank empty. The water stays as warm as the interior of the Escape and draws into the hot water tank or any other interior plumbing. I found that the water lines would quickly freeze up when drawing from the fresh water tank before the tank itself would freeze.

[huskersteffy]

An alternative is to use the winterizing valve and draw from a water container (I use a 6 gallon) that I place near the water pump.

Great idea.

[Crash]

Originally Posted by huskersteffy

You may not have to run any wires to the existing pump. Once your "Normally Closed" valve opens via your temperature switch, the pump will kick on as it detects a loss of pressure.

Also, you may want to consider using a single point temperature sensor mounted in a corner of the fresh water tank (may have to drill hole unfortunately), since a capillary type sensor kind of averages the temperature along its length. The way you things sketched out, the sensor will immediately detect the hot water coming from the heater and then shut things off.

Both of these are great ideas! Thank you.

[Crash]

Originally Posted by Centex

... routing the recirculation via the freshwater vent tube rather than the fill pipe. The vent tube, being a smaller smooth type may be easier to match with a Tee fitting.

That is a great idea! Thanks

[tdf-texas]

Originally Posted by Crash

We are looking for a way to ensure the fresh water tank doesn’t freeze during short ski trips – a night or two. We will put RV anti-freeze in the black and grey tanks - so they should be fine.

While we have a big BestGo battery, DC heating strips use a lot of battery power. As an alternative I found this interesting post recirculating hot water in an RV that uses the water heater instead of DC heating strips.

The idea is to use the hot water heater and water pump to recirculate the hot water into the fresh water tank. Note that we don’t need the fresh water to drink or cook – the focus is on being able to take a hot shower after a day or two of skiing.

This is simple in operation: you tap into the hot water line and put it through a ball valve. When the valve is open, hot water pours into the fresh water tank. The ball value is NC and opens using a mechanical temperature switch. Power comes from the 12 V circuit that powers the water pump with an additional rocker switch to disable the recirculation. A diagram is attached below.

To implement this, I would need to put a Y into the fresh water fill pipe. I don’t recognize the kind of flexible pipe that Escape uses for the fresh fill line; anyone have a pointer?

Would it be easy to put in a T or Y junction? Guessing I might need to 3D print a nylon Y connector with openings for the existing line in, hot water in, and capillary tube.

Any other concerns or suggestions on doing this?

Be forewarned. The PVC tubing Escape uses for the fresh water fill lines is NOT rated for hot water use and will burst fail.

For an example, do a search for the Reaces's USA tour to replace all the PVC tubing he used for the bathroom hot water lines in the 2017+ 21s.

[alanmalk]

Originally Posted by tdf-texas

Be forewarned. The PVC tubing Escape uses for the fresh water fill lines is NOT rated for hot water use and will burst fail.
...

Only consider that the PVC line if used as a hot water re-circulation line is under no significant pressure since it is open ended into the fresh water tank, which in turn is not pressurized. It might sag from the heat but unlikely to "burst".

[elongest]

My E-19 has the fresh water tank installed inside under the bed for winter camping. You do loose a bit of storage space. You would need to put inside shut off valves to the outside shower.
Eddie

[Crash]

Originally Posted by alanmalk

Only consider that the PVC line if used as a hot water re-circulation line is under no significant pressure since it is open ended into the fresh water tank, which in turn is not pressurized. It might sag from the heat but unlikely to "burst".

In thinking about this... the PVC line is normally used as the tank vent. If the recirculation driven by the water pump is putting water in at pressure, and at the same time drawing water out of tank, then the in and out rate should be the same. However, it seems like there might be some risk of it overflowing when it first starts.

Thoughts?

[alanmalk]

Originally Posted by Crash

In thinking about this... the PVC line is normally used as the tank vent. If the recirculation driven by the water pump is putting water in at pressure, and at the same time drawing water out of tank, then the in and out rate should be the same. However, it seems like there might be some risk of it overflowing when it first starts.

Thoughts?

The tank vent is also designed to be an overflow outlet if the tank is overfilled. Worst case - loose a few ounces? ? ?

[Crash]

Originally Posted by kstock11

An alternative is to use the winterizing valve and draw from a water container (I use a 6 gallon) that I place near the water pump. I leave the fresh water tank empty. The water stays as warm as the interior of the Escape and draws into the hot water tank or any other interior plumbing. I found that the water lines would quickly freeze up when drawing from the fresh water tank before the tank itself would freeze.

Thanks kstock11. After looking over all the replies and options, this looks like the most reliable way to address the short ski trip challenge - and it is much simpler to get working.

Originally Posted by elongest

My E-19 has the fresh water tank installed inside under the bed for winter camping. You do loose a bit of storage space. You would need to put inside shut off valves to the outside shower.
Eddie

The back side of the outside showers are within the space that would be heated. Guessing that some foam insulation behind the outside shower cover and keeping the back warm should be enough. What do you think elongest?