Out With On-Demand Water Heater

[JimD]

Ever since I bought my 2017 Greyhawk I have hated the on-demand water heater. I mostly boondock and that water heater just wastes too much water and never really got hot enough even when set to its 124 degree max. Hot water to the bath faucet was a joke and showers were an effort in frustration.

I knew what a conventional water heater was like as I had one in my old Lance camper and loved it. While trying to taker a shower recently when camping at New Years I finally just said screw it and made up my mind to swap it out.

I am currently camping in the desert and have been using the new water heater and I absolutely couldn't be happier. I can finally wash and actually rinse dishes using HOT water without draining my tank. My wife now can get hot water in the bathroom so she is very happy.

I purchased a Suburban SW6DE water heater which is a 6 gallon direct-spark ignition unit with 120 volt capability. I thought if I was going to the trouble of replacing the thing I might as well add 120 volt to it.

The install was not too difficult. Size wise the new unit just slid right in. I did modify the hoses to fit the new outlet locations but that was fairly easy after I bought the crimping tool. I have never worked with PEX tubing before but it was a lot easier than I thought.

I had to increase the length of the propane hose as the old one wasn't long enough to reach the new connector. I just added a 3 foot propane hose extension. Very easy!

Running the 120 volts was the most labor intensive as I installed a new dedicated 20 amp circuit. I used non-metallic Liquid-Tight Conduit to route the wiring from the circuit breaker panel under my bed to the water heater. I had to punch a hole in the floor and route the conduit a short distance under the coach to a wall area by the shower where I could bring it back up. It then routed through the wall to the water heater area. I used the water proof conduit because it was run under the coach.

I put a junction box at the water heater and installed a water heater relay in it so I could switch the 120 volt on and off as I wanted. This version water heater does not have the built in relay so you must add the external relay to be able to switch it on/off from inside the rig. Otherwise you have to go outside to flip the built-in switch.

Everything is working as expected. I found that it takes about a half hour to heat up a cold tank to full temp using propane. If you use propane and 120 volt at the same time, which you can do, it shaves 10 minutes off the time.

I will never go on-demand water heating again even at home. You have to run the water too hard to get the heater to come on.

[JFlightRisk]

Good job! Your experience will surly be of help to others that wish to make the same swap out.

[seanreit]

Great story, but please don't completely dismiss instant home water heaters. I've been using this for almost 2 years and have had ZERO issues, more hot water than we can use:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

We also installed a watts water loop: https://www.amazon.com/dp/B000E78XHG...dDbGljaz10cnVl

We always have hot water at every faucet instantly.

Anyway, that Suburban water heater is going to work great and last long time! And if you can heat the water with solar electricity, you are going to be able to boondock a long time.

I too installed a heating element in my onboard water heater using a drain kit, hooked it up to one of my inverters that come off my LIFPO4 batteries so I can get free heat as well. Good Times!

[EA37TS]

Originally Posted by seanreit

Great story, but please don't completely dismiss instant home water heaters. I've been using this for almost 2 years and have had ZERO issues, more hot water than we can use:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

We also installed a watts water loop: https://www.amazon.com/dp/B000E78XHG...dDbGljaz10cnVl

We always have hot water at every faucet instantly.

Anyway, that Suburban water heater is going to work great and last long time! And if you can heat the water with solar electricity, you are going to be able to boondock a long time.

I too installed a heating element in my onboard water heater using a drain kit, hooked it up to one of my inverters that come off my LIFPO4 batteries so I can get free heat as well. Good Times!

Interesting. Your water loop specifically says "Do not use with tankless water heaters"

My tankless system at the house is a POS and I refused to look at any motor homes that had one. IMHO, there is too much difference between campground water systems and when there is low flow with a tankless system there is no hot water. Low flow can also be caused by sediment or mineral build up in the faucets. Have had our tankless system for over 10 years and hate it. We are hoping it goes out so we can justify a better system. The system was installed by the contractor when the house was built.

[hoppers4]

Wow, you persisted longer than I have the patience for. My first two outings convinced me that it would never work right. I replaced it with the same unit you did after only a couple of months of owning the rig.

[AKRUEBBE]

Their lack of popularity is probably the reason tankless is no longer offered as an option.

[muckinfuss]

I put one into one of my rental homes to replace a tank. Turns out those things are like a wife I once had.....really expensive up front, never delivered on the promise, high maintenance and finally stopped making any sense at all.

[mercman]

Hmm, interesting thread.

My situation: I'm living in a 2018 264BHW with the Baja package while I'm building and earth sheltered home. I am installing a stand alone 1000 gallon water tank and do now have shore power and septic hookups on my property. While I haven't used the water features of the TT i have been considering installing an on demand water heater instead of using the 6 gallon tank heater that came with the trailer.

It is just me (and my two German Shepherd Dogs!) so I'm unsure how much demand that I'll have. I am pretty conservative on water usage.

Anyone have any experience that might be of help to me?

Thanks,

Kurt

[muckinfuss]

Re-read the original post. All your answers are there. First misstatement is 'on-demand'. They do not deliver hot water any faster than a tank would, and in my experience....much slower. If you are not a high user of hot water, then I'm not sure what the benefit is. You can switch to electric on the 6 gal and save propane if that's your objective...you'll have true 'on-demand' hot water then and if you find you aren't as conservative as you think, flip the gas switch before using for fastest recovery, then flip it off when done.

[mercman]

One factor that is different for me vs. the others posting in this thread is that I am stationary and not RVing.

The weather here, in the winter, gets down to around -20 degrees which most folks do not 'camp' in.

My concerns are as to whether a tankless water heater will make more sense for me than the supplied water heater. It's a capacity issue more than a supply issue.

I am looking for feedback from those who might have experience with the conditions that I'm currently facing.

I guess that since the cost of the smaller tanks less heaters isn't that great I could parallel one across my supplied heater as insurance. Better now than when I have 6' of snow on the ground and it's subzero weather............

[muckinfuss]

No way I'd go that direction....I don't have to live in my unit as you are to know that.... There is no pilot, therefore the water only heats when there is flow that meets a fixed gallons per minute draw. A tankless sitting idle does not hold any heat in it's exchanger, water lines etc. My experience is that I've installed 4 gpm through 9 gpm units for residential.

I still can't see how you would be gaining anything positive from the switch unless your long term is to pull it out of the rv and reinstall in your finished home. But even then, I'm not certain that the transfer would be smooth or workable. A quick glance around the interweb will not yield an overwhelming thumbs up on tankless in any application except by those who make a living selling them. A ten gallon tank unit would be cheaper to purchase and a simple install. If you do the switch, keep the tank unit close at hand in case you need to go back to it. Good luck with whatever you decide.

[JimD]

If the water coming into the on-demand (or tankless) unit is really cold you may not get out the high temp you desire. These things raise the temp of the incoming water by a certain amount rather than just heating it to a max level. I watched my display which was set for 124 degrees. During operation that figure would fluctuate and most often was much lower than I wanted.

Just for the fun of it I looked at the spec of a gas home unit. Its spec showed a water flow at a 35 degree temperature rise. So for this unit, at home, if your water was 60 degrees you would get 95 degree water out. Colder input would be even worse.

Before you make a decision I would look at the specs for the unit you would be buying and see if it indeed would get your real cold water up to a "hot" level. You may end up with a warm water heater rather than a hot one.

[muckinfuss]

Originally Posted by JimD

If the water coming into the on-demand (or tankless) unit is really cold you may not get out the high temp you desire. These things raise the temp of the incoming water by a certain amount rather than just heating it to a max level. I watched my display which was set for 124 degrees. During operation that figure would fluctuate and most often was much lower than I wanted.

Just for the fun of it I looked at the spec of a gas home unit. Its spec showed a water flow at a 35 degree temperature rise. So for this unit, at home, if your water was 60 degrees you would get 95 degree water out. Colder input would be even worse.

Before you make a decision I would look at the specs for the unit you would be buying and see if it indeed would get your real cold water up to a "hot" level. You may end up with a warm water heater rather than a hot one.

Yep. Real life example...most all ground water and city supply is at approx 55-60 degrees. An Eccotemp 4gpm unit will perform as follows...1.9 gpm will deliver 128 degrees at the unit. Temp drops over distance to output. At 2.5 gpm, the unit shows 109-111 (luke warm in my book. At 3.3 or above, the unit shows 78-94. Fluctutation of temps at higher delivery rates is due to the 80% rule....any technology begins losing efficiency at 80% utilization...Tankless are no exception. No units I've experienced have ever delivered acceptable temps when approaching their 'listed' gpm.

[mercman]

All sounds reasonable! I am going to heat the 1K tank to around 50 degrees but sounds like I won't get 'hot' water from this set up.

I'll try the 6 gallon tank and see how well it produces and look at installing a bigger tanked heater. I plan on having my home done enough to move into by next year so one more winter in the TT should be my goal.

I plan on selling the TT then or perhaps buying an acre in AZ or NM to set it on........

[Jagiven]

Glad you like the new water heater. If a person always had full hook ups, it might be ok. But I think I have had full hookups maybe twice ever. So no way!

I have an on demand at home at it works great. There was definitely a learning curve. Especially about that slug of cold water you get every-time you turn the faucet off and back on. We dropped our gas consumption at home down from 3.5 therms a day to 1/2 therm. Probably would be less, but the kid takes extremely long showers. Might be the one downside.

[Rice1951]

I’ll throw a different perspective at this thread. My coach came with the Girard on demand system and I agree it did not live up to its billing. Everything everyone has mentioned in the previous posts was all true for the Girard system. I had it replaced with a Truma AquaGo Comfort model.
Night and day difference. Works just like at home. Turn on the hot water and adjust to your liking by mixing in cold. No choosing a temperature, works with low water pressure and I am completely satisfied. The only drawback I see to the Truma is that it runs on propane only but for me that’s not a concern.
So on demand systems can differ with manufacturers. Probably no different than a lot of other things we buy in our lifetime. You just need to find what works for you.