New Atwood Tankless

[lewster]

Originally Posted by mutcth

Referring back to an earlier question, how much of a current draw is there for the instant ignition? Not a fan for parasitic loads when boon docking...

And how exactly do you winterize them? Is there anything to drain out?

Another thing to add to the list of future toys...

Tom

The DC loads are approximately the same as a conventional DSI tank water heater....not much! Thee might be a small circulating fan that will use some DC (perhaps less than an amp) while the unit is operating.

Winterizing is done like anything else; run pink propylene glycol RV antifreeze (PG) thru all hot and cold water lines until it comes out all of the faucets, ice makers, washer/dryer lines, etc. Add some PG to your p-traps and toilet and you're done.

As there is no water storage tank in the water heater, there is no need for a by-pass system. just be sure that the PG flows thru the copper coils in the water heater's heat exchanger, as it will if you have PG coming from your hot water faucets.

[REDNAX]

(I always liked the cheap case of vodka as an alternative to the pink stuff as mentioned years ago by someone here).

Thanks for the info on these heaters.

.

[Skater]

Originally Posted by REDNAX

(I always liked the cheap case of vodka as an alternative to the pink stuff as mentioned years ago by someone here).

A woman in our local unit wants to try this. Of course they just built a heated garage that can store both of their trailers, so it's a moot point for them now.

Back to the tankless - I'm following this thread with interest, too, and can't wait to hear what people say about them after using them a while.

As it stands now, I usually turn off the water heater during the day and at night, only turning it on in the morning before we officially get out of bed (I get up early to feed the cat, then crawl back in bed, so I usually turn on the water heater then), and we'll turn it on before dinner so we have hot water for dishes. As others have noted the tank will keep the water at least warm enough for washing hands and the like the rest of the time.

Given that usage scenario, a tankless isn't going to save a lot of propane and may actually use a bit more. The advantage of the tankless would be not having to worry about switching it on and off, yet still having hot water at any moment.

The point that the water doesn't come out at a specific temperature was an interesting one - it only raises the water temperature a certain amount, so if your input water is very cold, your "hot" water isn't going to be as hot as usual. I've read stories from people with them at their houses that had very cold incoming water, so the tankless WH didn't do very well for them. This is an important point for me, because we camp in the winter weather as well, and water coming out of our fresh water tank in the cold weather is VERY cold, so the tankless WH might not be a good idea for us in the camper. (I still think it'd be great at our home, though.)

(On the other hand, this winter, we were having issues with major temperature fluctuation out of the regular water heater as the pump kicked on and off. By "major," I mean "from too cold to too hot without touching the shower handle." So it's not like we're having a wonderful experience with the current setup in winter, either.)

[lewster]

If you look at any water temp chart that usually comes with a tankless water heater, you can see how hot your output water will be depending on two factors: temps of the inlet water and the flow rate.

Tankless units are rated for a set degree rise at a specified flow rate and inlet water temp. Adjust either of these parameters and you can still get very hot water; simply turn down the volume of hot water coming from your faucet.

[crispyboy]

My concern with a tankless water heater would be if this setup would use more water than the standard water heater. I have been around household tankless heaters and it seems that you have to flow a lot of water before you get hot water at the tap. This means more water from the freshwater tank and more in the grey water tank. I would rather eat more propane versus dealing with more waste water.
Does this make sense?

[BigAl]

As far as gas consumption goes, we often turn the heater off when we go to bed and turn it on again in the morning. The water is still quite hot in the morning and it only takes ten minutes or less to be at full temp.
The tankless heater seems very expensive. Having 5 gallons of water in the tank actually increases your capacity and if it's an issue don't fill your freshwater tank to the max.
Al

[Andrew T]

My only concern with the tankless heaters for us in the great white north is freezing when using the Airstream in cold weather. The 3/8" copper lines filled with water are exposed directly to outside air so it would not take very long to freeze and split them. I would not be a problem if you were using water steadily but a 4 hour drive in 0 degree weather or 8 hours without running water would do it in.

Though parts of the tank style heater are expose to the outside air it takes a long time to freeze 6 gallons. They did not have an answer to this problem the last time I spoke with them. You could have a circut that would keep firing the heater in cold weather to prevent freezing but if the system stopped working for any reason you would have split lines.

Andrew T

[CrawfordGene]

Andrew, very good point. Glad to see you asked them directly.

Perhaps you could put insulation between the heater and the exhaust door, but the danger is someone not remembering to remove it when they turn on the water heater. The only way to make that safe is a switch that to be turned on in that compartment after removing the insulation.

Gene

[truckasaurus]

Frank. PT's Showermate (the marine version of the RV500) vents through the floor and is good for venting up to 20' through 2" hose. It has a tiny fan in the exhaust. I bought mine maybe 18 months back and I think it was available for sometime before that. It's a really nice product just a little bit more $s