Tell me why not to use this hot water heater.

[Christyhicks]

Ok, having owned and worked on tankless water heaters for years, I'll tell you what little I do know.

This appears to be a imported unit and not likely approved for any use in the U.S., which is why it doesn't have any manufacturer info on it or ratings from safety agencies.  Basically, you're on your own and installing it at your own risk knowing that it's probably not been tested for safety and likely, warranty will realistically be zilch.

It appears to be built in a similar style to the, single fixture, "lower end" tankless units, with basic water/gas control valves that likely restrict water and gas flow to adjust temperature.  It has 1/2" gas inlet and is rated at a fairly low Btu, so that's a plus when trying to use it on a low pressure/low flow situation such as an rv.  Often, the larger "lower end" tankless units won't activate without a fair amount of flow, and will drop out on reduced flow, so you really want low Btu's for the low flow you'll have in an RV.  Since this one will produce hot water at 2.75 gallons per minute, I doubt you'd have a problem with not enough or too much hot water.  It clearly is designed to be vented, which is why they say it needs to be installed outdoors.  It is a small unit, so likely would fit into a bay or closet pretty easily, as long as you watch your clearance requirements.  The biggie would be the proper venting of both intake combustion air and the venting of the flue gases.  Since it does not have an "intake" pipe, you will need to ventilate the closet or bay to the outdoors with sufficient fresh air.  Keep in mind, this means you'll have plenty of hot air in the Summer, and cold air in the Winter, circulating around this water heater at all times.  Fresh combustion air is just as critical as flue exhaust.

Now, flue exhaust it a little more difficult to determine.  Since this unit doesn't have an exhaust blower, you can assume that it is likely designed to exhaust on double wall type B vent.  On the other hand, you probably would be safter to use category III gasketed flue pipe, just to keep the CO where it belongs, outside.  Read the instructions and follow all clearance requirements for the flue pipe.

This uses batteries for the spark ignition. . . commonly done on lower end units, and they usually last quite awhile.

The drawbacks are:

It does mention a minimum pressure of 35 psi, which could be a problem if that's true. With the low Btu input and flow output, I'm surprised it would require that much pressure, but it is possible.  If I bought it, I would play with the tempurature/gas controls to see if I could get buy with lower pressure.

It's not been safety tested and approved, so if it were me, I'd have a CO detector in the compartment and proper flue exhaust, just to make sure I wasn't creating a hazard.  If I didn't understand how to run the flue in a safe manner, I would not install it.  I would also probably put a temperature sensor in the compartment to make sure it wasn't getting too hot or too cold in there.

It's really cheap, which is good for you, but also makes you aware that it may not have safety features either.  So, play at your own risk.  IMHO, Christy Hicks

[JohnEd]

Christy,

Thank you for a most excellent response.  Great detail and explanation....without the math.


Clif,

She said "it's OK....mostly".

John....   I crack myself up. 

[Eagle Andy]

Here a picture of what the po had when I bought our Eagle I never used it and I think he only had as a back up . I took it out because I had no access to the 20 gal water heater. He had a small blower motor in the exhaust pipe . FWIW .

[BG6]

What are all the reasons why I would not want to use this hot water heater?

Obviously it would have to be mounted outside, maybe on the backside of the bays... or in the bay and vented with a chimney.
i'm sure it is a bad idea or else more people would be using them.

First off, it's not a major brand.  Where will you get parts?  OTOH, it's cheap enough that you could buy two and throw one in storage, just in case.

Second, it's an outdoor-ONLY unit ("any open area with excellent ventilation").  That means carbon monoxide leaks, even with a chimney, so you can't put it in the bays.  Your only option is to mount it on the side or the back of the coach.  Depending on the size, it might not look too back on the back, especially if you have a ladder to balance out.  If you mount it on the engine cover, you will need to use flexible (not "bendable")  water and propane lines.

Third, are you happy with 2.75GPM?

If these all work for you, then it's hard to say bad things about someone with that many 100% feedbacks.

[James77MCI8]

I have installed the electric units in homes. The one I install require 2 separate 40 amp circuits to operate. Though they use an enormous amount of power when "On". The savings is realized because you are only heating water as you need it and not using power to maintain the temperature when the water isn't needed.. The same applies to gas. I am referencing heater that will supply hot water for the entire house. The point of use models(electric) use much less power.

[Christyhicks]

Yeah, my big gripe with the electric ones is the inability/extreme cost to replace elements when they fail.  Usually, the homeowner just buys a new unit.  Shameful IMHO.  Perhaps you have access to a better line of heaters than we do.  Christy hicks

[philiptompkjns]

Wow, a lot of good info and good replies in here, thanks.

The only thing that was pointed out that I had not  really though of was the flow rate on the low end not being able to kick the heater on in a "low throttle" situation. 
If that is a huge  problem I could probably install a manual override switch in the shower to force it on for short periods of time.
And I'm not really doing anything  as ghetto as bolting it to the back of the bus, I'll find someplace to put it  though.  I will update this thread in the future if I actually install it.

[JohnEd]

anything  as ghetto as bolting it to the back of the bus, 

Now that is funny.  Thanks

[Slow Rider]

Since we have so many knowledgeable folks in this thread perhaps you can explain something that has always perplexed me.  Why if the water is already hot, do you want to heat it again?

Expiring minds want to know.......

Frank

I mean after all it is a hot water, heater correct?

[JohnEd]

I mean after all it is a hot water, heater correct?

Nick,

After your rested?

John

[philiptompkjns]

NO, you guys have it wrong.
I'm getting a  hot, water heater.
Hot as in bad @$#.