Second Water Heater Install

[Road King]

...anyone installed a second water heater to supplement the factory installed 6 gallon water heater?

I am thinking of installing an electric 6 gallon water heater. I looked at the propane and electric tankless heater but decided to go with a 6 gallon mini tank by Stiebel Eltron SHC 6.

What say you?

Thanks!

[flybouy]

Originally Posted by Road King

...anyone installed a second water heater to supplement the factory installed 6 gallon water heater?

I am thinking of installing an electric 6 gallon water heater. I looked at the propane and electric waterless but decided to go with a 6 gallon mini tank by Stiebel Eltron SHC 6.

What say you?

Thanks!

I'm a little confused, not new for me. So if I read this correctly you replaced a gas wh with an electric only wh and are now wanting to add a second one? The biggest challenge besides space would be having the amperage to operate 2 of them on a 30 amp service.

I'm guessing the "waterless water heater" was supposed to be tankless. I don’t know of any tankless units suitable for showering that would operate on 120 vac. There are small point of use water heaters that are ok to heat water to wash your hands but that's it.

[Road King]

...thanks for pointing out the typo. I corrected it to "tankless".

I still have factory installed dual powered (electric & propane) 6 gallon water heater and keeping it. I want to install another water heater to give me additional hot water for the showers to use in tandem with the OEM water heater.

I researched what I needed and decided on the 6 gallon electrical water heater (SHC 6) not a tankless one. There are electrical tankless water heaters but too much electrical draw. Therefore, I chose a 6 gallon tank which only draws 11.3 amps when heating. I can monitor my electrical usage but as an alternative, I was thinking of plugging it directly to the 20 amp shore power.

So you know, I did think of a tankless water heater powered by propane. It was quite expensive but really didn't want to take the OEM out since it's still brand new.

[flybouy]

Are you aware that for quicker recovery that you can use the OEM running the gas and electric simultaneously?

[chuckster57]

I would simply swap it out for an “on demand” hot water system, that way your only limit is gray tank capacity or LP. Truma makes a very nice unit (reflected in the price) but I can say from experience, they are reliable.

[Road King]

Yes, I do. However, I don't want to take Navy showers. :-(

I want more hot water for my showers.

[flybouy]

In my thinking this will be the issue, let's call the tank closest to the water source tank 1 and the tank closer to the shower tank 2. Turn on both tanks and if unused both tanks will come up to temp and shut off.

Turn on the shower and tank 2 will empty with water forced out by the contents of tank1 and tank 2 will not call for heat as the water from tank 1 is pre heated.
Once tank 2 is empty you will have two tanks of cold water to heat. Basically like having a 12 gal tank. I don’t know how long of a shower you desire but that setup wouldn't come close to providing an "unlimited supply of hot water".

[sourdough]

Aside from the installation of a 2nd tank (which I think isn't going to accomplish the goal);

I understand not wanting to take Navy showers, neither do I. I guess coming from an environment of no shower, to washing up in a freezing stream, to the old "sun showers", to a 6 gal. navy shower then to the DSI/electric 6 gal. water heater I thought the DSI heaters were the cat's meow....MAJOR cat's meow.

With a reg. water heater the hot water did run out, and quickly, so a quick navy shower was in order and 2 showers in a row was out of the question. With our first DSI water heater I thought I had to do the same (first time out I only ran it on electric so a navy shower was called for). After figuring it out neither DW or I ever ran out of hot water when taking fairly long showers (as long as I do at the S&B). Didn't take 2 in a row because it would get cool but for one it was more than adequate. I couldn't tell from your response; are you running the water heater on both electric and LP modes at the same time to shower? Are you sure the heater works on both modes independently? If not and it's a Suburban there is probably a switch on the water heater that has to be on for the electric side to work...is it on?

If everything is working as it should it may be that the expectations are more than the RV can provide....or was designed to provide even if you try to modify it.

[Falcon67]

Seems to me that unless you have a bodacious fresh and grey water tank, the "Navy" shower is the only way to get it done. Our 220 has a 27 gallon grey and that's max 4 days two people, Navy style using the least rinse possible, washing pans outside and using hand sanitizer as appropriate. The race trailer has a 6 gallon electric water heater and we've never had an issue running out of hot water.

That all said - at drag strips, you're "boondocking" so I could possibly see an issue if you were hooked to a water supply at a camp ground.

[Road King]

...after some more research, it looks like having a mini-tank does not give me the ability to drain it after use. Therefore, the mini-tank is out.

I guess the next step is tankless. I still don't want propane because I will need to make an exhaust outlet and still don't want to purchase the full-blown Truma or Girard tankless water heater to replace the OEM.

It looks like I will consider an electrical tankless heater.

[travelin texans]

Would it be more practical with less major surgery on the rv to just replace the 6 gallon with a 12?
Our last 5er with a 12 gallon heater + wash machine + dishwasher + 2 adults fulltime & never an issue with hot water.

[JRTJH]

From the way I see it (for what it's worth) running out of hot water is a result of much more than the volume of water in the water heater tank.

First, there's the inflow cold water temperature.
Second, there's the outflow of hot water and how fast the tank empties.
Third, there's the recovery rate for the water heater.
Fourth, there's the flow rate for the shower head.
Fifth, there's the water pressure that "creates/influences" the flow rate through the system.

The recovery rate for a Suburban 6 gallon water heater is the same as for a 12 gallon water heater (17.1 GPH with gas/electric both operating). The difference in the two is only the amount of hot water available at the start of the shower (assuming the tank is full of hot water.

Most "OEM showerheads" have a flow rate of 3.2-4.2 GPM at a pressure of 35PSI. That means you'll start running out of "first tank hot water" in about 2-3 minutes.

Replacing the showerhead with an Oxygenics type will reduce the flow rate to 1.4-1.8 GPM. That will effectively "double the shower time on the first tank".

With only electric heating, expect the best "time to BRRRRR" to be around 3 minutes with an OEM showerhead and about 6 mnutes with an Oxygenics.

With only gas heating, expect the best "time to BRRRRR" to be around 6 or 7 minutes (about double the time because the BTU's replacing the removed heat is a bit over double what's available with the electric element only.

With both gas and electric heating, expect the best "time to BRRRRR" to be around 9-11 minutes.

10 minutes with a 4GPM showerhead is about 40 gallons of water, half of which is hot when mixed with half cold to adjust the temperature. That's about 150% of the gray tank capacity, so the trailer becomes a "one shower shack" when boondocking.

In a campground with "endless water and a sewer connection" the water heater can keep up with a Oxygenics 1.4 GPM shower for about 10 minutes. That's about a 15 gallon flow, 7.5 hot/7.5 cold.

Some people prefer the Oxygenics "feel" some don't like it.

Before spending $500 to 800 on a "on demand water heater" that only operates on propane, I'd look at a pressure regulator to reduce the water pressure and a "volume reducing showerhead" that will further restrict water flow in the shower while still providing a desireable water feel.

I'd say, that the "design criteria" for a RV shower is not to replicate a S&B "endless shower capability" but rather to provide a "restricted waterflow shower" that will "work good enough with a liimited supply of water and waste water storage"... Trying to replicate a S&B shower in a small, inexpensive RV isn't easy to do and certainly won't be cheap.

[Road King]

Originally Posted by travelin texans

Would it be more practical with less major surgery on the rv to just replace the 6 gallon with a 12?
Our last 5er with a 12 gallon heater + wash machine + dishwasher + 2 adults fulltime & never an issue with hot water.

...let's just say it's cost-prohibitive. Trying to get the best bang for the buck. I want to look at all available options before plunking down good dollars.

I'm cheap.

[LHaven]

If I were you, I'd try the unit out before buying it. I've installed and maintained NG on-demand WH, and I'm dubious about electric being either effective or economical.

[apachewolf]

WOW…………..My Laredo 240MK must be something else. Got it new in 2015 have NEVER had a hot water supply problem. I did install an Oxygenic shower head AND ad shut-off valve on the shower hose. Wife takes her shower first and I go next. So far have not run out of hot water. 99.8 % of the time the WH Standard 6 gallon) is run on electric and no problem ever encountered. The shut-off valve is something I use the wife not. I turn it to a trickle while soaping up and than turn it to full flow for the rinse. A few years ago the threaded part at the bottom of the handle broke, I contacted Oxygenic and they send for free of charge 2 new shower heads since they did not know the color of the one I had. Great service in my opinion. On the Lance TT prior to this one we also used the Oxygenic shower head, with no problems.

Happy camping and showering.