Water Heater question

[larryburt5@icloud.com]

After much thought, we've decided to install a plug-in only small tank water heater in our soon-to-be converted Promaster 136 HT van. The Bosch Tronic 3000T Tank 4 gallon is our current idea, but I've noticed there is no drain, which will make flushing and prepping for winter storage difficult.
Looking for advice about how to drain the system or do you know of a similar small tank electric water heater that has a drain?

[RT-NY]

Originally Posted by larryburt5@icloud.com

After much thought, we've decided to install a plug-in only small tank water heater in our soon-to-be converted Promaster 136 HT van. The Bosch Tronic 3000T Tank 4 gallon is our current idea, but I've noticed there is no drain, which will make flushing and prepping for winter storage difficult.
Looking for advice about how to drain the system or do you know of a similar small tank electric water heater that has a drain?

I believe that the only way to drain that tank is to disconnect the cold water line and to siphon out the water (or disconnect both lines and turn it upside down). Another thing to keep in mind: I believe that in order to change the anode on the tank you have to drain it and remove the front cover and heater element and that the anode is of a non-standard size and not so easy to find.

[larryburt5@icloud.com]

Originally Posted by RT-NY

I believe that the only way to drain that tank is to disconnect the cold water line and to siphon out the water (or disconnect both lines and turn it upside down). Another thing to keep in mind: I believe that in order to change the anode on the tank you have to drain it and remove the front cover and heater element and that the anode is of a non-standard size and not so easy to find.

Thanks, those are problematic issues. Do you know of a small tank electric alternative with a drain and easier anode repair? I don't want an on-demand unit because they waste water with the initial lag and high minimum flow rate. Our van converter doesn't want to use a standard propane unit because of the large side opening required, difficult to place in a small van. The Whale Expanse or Propex Malaga are small tank european propane units, but apparently aren't certified for USA use. I'm starting to think hot water isn't worth it, we can always heat water on the stove.

[avanti]

If you switch to hydronic heat, you can add a zero-waste, truly instant hot-water heater via a flash-plate heat exchanger.

[larryburt5@icloud.com]

Thanks, hydronic heat/hot water sounds interesting. What brand/model would you suggest for a small class B, Promaster 136WB High top?

[avanti]

Originally Posted by larryburt5@icloud.com

Thanks, hydronic heat/hot water sounds interesting. What brand/model would you suggest for a small class B, Promaster 136WB High top?

There are several similar systems of hydronic heaters (both gas and diesel). Probably the most popular is Eberspächer, known in the US as "Espar", but there is not a huge difference among brands. A company called "Rixen's" in Oregon makes a high-quality turn-key Espar-based kit specifically for vans. Probably the easiest approach, but not the cheapest. They are a quality business. That is what we have in our current Sprinter, and am also using in our new Transit rig.

[GeorgeRa]

New heater is coming à la European Truma, it will be gas, LPG or diesel powered. If you can wait it could be a good option.

My suggestion is to look energy sources for 3 energy hogs upfront, heating, water heating and stove. LPG is a good energy source for all three. With potent batteries you can use an electric stove but for heating and water heating you practical have to use either gas, LPG or diesel.

Most of RV in NA use LPG, B-class is special, a very special bunch disliking LPG. It is possible that your converter can’t legally install LPG so is recommending gas. Hydronic heating like Rixen (using German Eberspacher heater), Timberline (using Russian heater) or home brewed one can provide heating and water heating.

I opted for Espar Airtronics D2 for space heating, Espar Hydronic D5 with Isotemp marine heater for water heating and Origo alcohol stove (no longer in production).

Doing conversion again I would likely opt for the new Aqua Hot, and regular RV stove powered by LPG.

[larryburt5@icloud.com]

I agree about the three energy hogs: space heat, water heat, cooking should be done with LPG/Gas/Diesel. Gas engine in my Promaster. I'm partial to LPG over gas for a variety of reasons, so not going with hydronic unless there is an LPG hydronic system, but prefer to have separate air and water heating. We'll have a Propex furnace and two-burner propane cooktop. First choice for water heating is the Truma AquaGo Comfort or better yet, the Comfort Plus with recirc, but my converter does not want to cut that big a hole in the side for my classic Westy layout, doesn't fit well. Second/third choice are the LPG mini-tank Whale Expanse or Propex Malaga, but AFAIK not available/approved in US. Maybe someday can retrofit, but for now it looks like a small tank electric, plug in only, is the way to go. Bosch 3000Tank 2.5 or 4 gallon is one choice but no drain and I've heard is hard to service. Looks like a better option is the marine grade aluminum Whale S300EW 120V electric, 3 gallons, 1250Watts, includes a drain valve. We can also heat water on the propane burner and may also get a 300W tea kettle or 600W microwave.

[GeorgeRa]

I forgot to provide the new space/water heater link - https://rvbusiness.com/aqua-hot-anno...-water-system/

Can you share who is going to do your conversion?

[mkguitar]

Originally Posted by larryburt5@icloud.com

. I'm starting to think hot water isn't worth it, we can always heat water on the stove.

what will your use be ?

We need to get water hot for washing produce for meal prep, then dishes etc.

I use one of those black shower bags for most of that, leave it out for the afternoon

We do have a hot water heater, we don't use it often.

We rarely shower at the van though

[Rlum]

Originally Posted by larryburt5@icloud.com

Thanks, those are problematic issues. Do you know of a small tank electric alternative with a drain and easier anode repair? I don't want an on-demand unit because they waste water with the initial lag and high minimum flow rate. Our van converter doesn't want to use a standard propane unit because of the large side opening required, difficult to place in a small van. The Whale Expanse or Propex Malaga are small tank european propane units, but apparently aren't certified for USA use. I'm starting to think hot water isn't worth it, we can always heat water on the stove.

I have a Truma Aqua Go Plus. You are right, there is a lag to get hot water. I measured it and waste about 16 oz of water each morning. I am in the process of installing a purge system to return cold water to the fresh water tank. Looking at some 12 volt water valves and a couple of return lines from hot water connections to the fresh water tank.

[avanti]

Originally Posted by Rlum

I have a Truma Aqua Go Plus. You are right, there is a lag to get hot water. I measured it and waste about 16 oz of water each morning. I am in the process of installing a purge system to return cold water to the fresh water tank. Looking at some 12 volt water valves and a couple of return lines from hot water connections to the fresh water tank.

I have a pre-heat loop in our galley. Saves a lot of water if you have a long run from the heater to the sink--even if the heater is truly instant, as is ours.

The best way to do it is to get a little programmable timer/relay for the valve and control it with a button. So, you can program it to the appropriate time interval, and just press the button to prime the hot water. Works great.

Note that there is no need to go all the way back to the tank. You can just add a tee anywhere upstream of the water pump. Whenever the valve is open, water will loop through your return line and be replaced with hot water. Easy peasy.

[Rlum]

Originally Posted by avanti

I have a pre-heat loop in our galley. Saves a lot of water if you have a long run from the heater to the sink--even if the heater is truly instant, as is ours.

The best way to do it is to get a little programmable timer/relay for the valve and control it with a button. So, you can program it to the appropriate time interval, and just press the button to prime the hot water. Works great.

Note that there is no need to go all the way back to the tank. You can just add a tee anywhere upstream of the water pump. Whenever the valve is open, water will loop through your return line and be replaced with hot water. Easy peasy.

Thanks for information. Programmable timer/relay? I was thinking just a simple 12 volt water valve. Just open it after water heater has been on for 2-3 minutes. Turn on water pump and allow the cold water to return water heater incoming line?

[avanti]

Originally Posted by Rlum

Thanks for information. Programmable timer/relay? I was thinking just a simple 12 volt water valve. Just open it after water heater has been on for 2-3 minutes. Turn on water pump and allow the cold water to return water heater incoming line?

Sure. But, in our galley, you just press a button, wait till the pump stops running, and wash your face. (We don't have one in the shower, only because the heater is instant and very close to the shower, so it isn't worth it).

For $10, it was worth it to us to not have to deal with manual controls. Here is an example of such a timer (randomly chosen):

https://www.amazon.com/UCTRONICS-Tac.../dp/B07BT25J52

There are different flavors of timer. I am not 100% sure that this is the right kind, but I think it is.

[booster]

Be aware that the feedback loops only will work when you are on the water pump, not on shore water, unless you have a separate pump to make it circulate like they do on home systems. A bit of wasted water is less downside on shore water, but it would be added to the tanks.

[peteco]

Originally Posted by avanti

I have a pre-heat loop in our galley. Saves a lot of water if you have a long run from the heater to the sink--even if the heater is truly instant, as is ours.

The best way to do it is to get a little programmable timer/relay for the valve and control it with a button. So, you can program it to the appropriate time interval, and just press the button to prime the hot water. Works great.

Note that there is no need to go all the way back to the tank. You can just add a tee anywhere upstream of the water pump. Whenever the valve is open, water will loop through your return line and be replaced with hot water. Easy peasy.

In our Roadtrek 210P it is a long distance from the bathroom faucet/shower to the HW heater. Please provide more details on the setup for the loop.

[Rlum]

Originally Posted by avanti

Sure. But, in our galley, you just press a button, wait till the pump stops running, and wash your face. (We don't have one in the shower, only because the heater is instant and very close to the shower, so it isn't worth it).

For $10, it was worth it to us to not have to deal with manual controls. Here is an example of such a timer (randomly chosen):

https://www.amazon.com/UCTRONICS-Tac.../dp/B07BT25J52

There are different flavors of timer. I am not 100% sure that this is the right kind, but I think it is.

You said, I did not need to route the return line to the fresh water tank? If I just tap into the hot water just before the fixture and run this line back to the incoming cold water to heater. Will the pump pressure to sufficient to drive water into heater without being obstructed? What you suggested is much easier but I am concerned the flow might be an issue so am thinking about going back to the tank?

[avanti]

Originally Posted by peteco

In our Roadtrek 210P it is a long distance from the bathroom faucet/shower to the HW heater. Please provide more details on the setup for the loop.

Originally Posted by Rlum

You said, I did not need to route the return line to the fresh water tank? If I just tap into the hot water just before the fixture and run this line back to the incoming cold water to heater.

You don't go to "incoming cold water to heater". You go to incoming cold water to the water pump. Upstream of the pump is low-pressure and near the shower fixture is high-pressure, so the water will flow whenever the solenoid valve is open. Looks like this:
preheat_loop.jpg

As for control:
Just connect a pushbutton to the timer. Connect the solenoid valve to the relay on the timer. Program the timer to run long enough to make the water at the Sink or shower hot. When you press the button, the pump will start and the water in your new loop will circulate until the timer shuts it off.

You can use a valve like this:
https://www.amazon.com/gp/product/B085FXYL3Z

[Rlum]

Originally Posted by avanti

You don't go to "incoming cold water to heater". You go to incoming cold water to the water pump. Upstream of the pump is low-pressure and near the shower fixture is high-pressure, so the water will flow whenever the solenoid valve is open. Looks like this:
Attachment 13378

As for control:
Just connect a pushbutton to the timer. Connect the solenoid valve to the relay on the timer. Program the timer to run long enough to make the water at the Sink or shower hot. When you press the button, the pump will start and the water in your new loop will circulate until the timer shuts it off.

You can use a valve like this:
https://www.amazon.com/gp/product/B085FXYL3Z

Now that makes sense. As long as I install the return line below water pump or on the incoming side of pump, it should be fine?

[Rlum]

Originally Posted by avanti

You don't go to "incoming cold water to heater". You go to incoming cold water to the water pump. Upstream of the pump is low-pressure and near the shower fixture is high-pressure, so the water will flow whenever the solenoid valve is open. Looks like this:
Attachment 13378

As for control:
Just connect a pushbutton to the timer. Connect the solenoid valve to the relay on the timer. Program the timer to run long enough to make the water at the Sink or shower hot. When you press the button, the pump will start and the water in your new loop will circulate until the timer shuts it off.

You can use a valve like this:
https://www.amazon.com/gp/product/B085FXYL3Z

I like the solenoid. I am thinking I can just switch it on when the water heater is heating up. Turn solenoid and pump on an allow to run for 1 minute? A timer may be a bit much since do not use hot water same time of day. Sometimes very early and in warm afternoon for showers? I can just tap into the hot water line on two fixtures(bathroom & kitchen) and run to solenoid and then into water pump? This makes the set up easier and far fewer parts. Thanks for the ideas and engineering!