Atwood Tankless vs. PrecisionTemp?

[bredlo]

Looked through the first few pages of posts in the WH section, but haven't seen my question posed yet:

I've read PrecisionTemp's press release that insinuated they've more or less licensed the technology in their RV-5xx tankless water heater to Atwood.

I'm wondering if anyone has had any hands-on experience with the two units. Curious if there are differences in
- pricing (Google is showing roughly $750 vs. $1100?)
- physical size,
- build-quality,
- or functional capabilities between the two.

If the two units are pretty similar, it leaves me to wonder why Precision would've chosen to cannibalize their own sales? On the other hand, if the Atwood has fewer features... or is less robustly built - maybe it's an attempt to sell to the mass market while keeping the high end customers for themselves.

In the market for one or the other and trying to decide, as you might've guessed.

[CA_Tallguy]

Perhaps you have seen the thread I started where were discussing some of this now...

http://www.airforums.com/forums/f445...er-100360.html

You are correct on the price points.

My take on it is that atwood is aiming for the 6 gallon market more than the high end. Right now, I thin the PT is at 55k btu and is more optimized for the 10 gallon cutout. The atwoods are at 45k and 50k and are optimized for the 6 gallon cutout. The atwood manual does reference a 55k model that isn't available right now and isn't being discussed as far as I know. I wouldn't be surprised if atwood sold a rebranded precisiontemp for that size though it remains to be determined how much the atwoods actually are using from PT in all the units.

In any case, I'm sure that they've thought through all this and have a game plan in mind. Part of the business model has got to be the volume that atwood can provide through their distribution channels.

[bredlo]

Ah, I see the conversation progressed and included some comparison, yes. Thanks for sharing your legwork on the Atwood - I may pay the extra for the 10 gal. version of the Precision anyhow, but I'm still a month or so from having to decide for sure.

[CA_Tallguy]

Originally Posted by bredlo

Ah, I see the conversation progressed and included some comparison, yes. Thanks for sharing your legwork on the Atwood - I may pay the extra for the 10 gal. version of the Precision anyhow, but I'm still a month or so from having to decide for sure.

If it will fit your opening well then it is probably the way to go for tankless as you can get the nice aluminum door with PT. I decided it was more important to me to keep with the atwood 6 gal dimensions considering my trailer layout and existing unit. Good luck with your project.

[Alumaholic]

Tankless water heating has several drawbacks for the Airstream. The biggest drawback to me is trying to take a "Navy" or in my case a "Marine" shower.
A Navy shower technique is used to conserve water when boondocking.
Wet down.
Turn off the water (using the shower head on-off button).
Soap up.
Turn on the water.
Rinse off.
Using this technique, and a conventional RV water heater, a person can shower with 2 gallons of water.
The tankless water heater requires you to wait for warm water after each step a process that sends two or three quarts down the drain. (This is also a problem when boondocking because you fill up your holding tank faster )

The RV water heaters are so efficient and useful, why the fascination with tankless? Is this just a "green" thing?

[CA_Tallguy]

I did notice that the manual says not to take navy showers...

"A Note About “Navy Showers” When Dry Camping -
It is recommended to take a shower just like you would at home. That is, leave the water running through the entire shower. The hot water system is designed to deliver a continuous, comfortable flow of hot water and that’s the way it works best.
Shutting off the shower with the showerhead button wastes water. Each time this is done, the showerhead “trickles”, filling the hot water line with cold water. This cold water has to be purged from the line each time the showerhead is turned back on. Tests have shown that this will not save water."

I think that may be saying don't let the water trickle while you shower because that lowers the flow to where the water hater turns off and it won't be heated. I wonder if you can simply cut it off all the way - then maybe it will be similar to a normal water heater since cold hasn't gone through the heater without being heated?

I'm fairly new to airstreaming and the water heater in my unit isn't working, so I have no experience with old style or tankless. Just in my head I had a hard time thinking about heating a tank all the time, though I know people turn them on and off. People who have installed the PT units seem to love them so I figured I'd give it a shot.

[CA_Tallguy]

Here's what the PT manual says about navy showers...

"During a ‘Navy’ style shower water is cold for a short time after turning off and then back on -
When water flow is turned off the RV500 will also turn off. Turning the water on again will result in a few seconds of over-heated water and then a few seconds of cold water. Our software minimizes the duration of the cold water, but it takes about three seconds to sense the flow and ignite the burner. If you are not dry-camping enjoy your shower and let the water run. The RV500 is designed to provide unlimited hot water."

[Alumaholic]

Originally Posted by CA_Tallguy

I'm fairly new to airstreaming and the water heater in my unit isn't working, so I have no experience with old style or tankless. Just in my head I had a hard time thinking about heating a tank all the time, though I know people turn them on and off. People who have installed the PT units seem to love them so I figured I'd give it a shot.

We spend almost 30% of our 60 plus camping days boondocking each year and the rest in RV parks or campgrounds with full hook ups. Being able to take a shower every day or two and conserve water is an important consideration.

The tankless system would be a huge pain in the AS (Airstream Style).

This is our fourth Airstream and the water heaters just keep getting better and better. The one in our 2007 runs on propane or 120 volts AC. We turn it off at night to save energy, and we still have hot water in the AM, even in freezing temps.

If you never intend to boondock, you'll be fine. Sorry that you won't be able to attend this year's Abq Balloon Fiesta Rally or the White Sands Rally; there won't be any hookups.

You get my point. A neighbor traded his 2009 fifth wheel (that he dearly loved) for 2011 by the same maker. They didn't tell him they had incorporated tankless water heaters into their latest design. He had to pay to have a conventional RV water heater installed. He and his wife only boondock, and they were miserable with their new purchase.

[CA_Tallguy]

Here's a solution I found posted on the net ...


"I addressed the problem with a little plumbing. I installed a line and valve between the hot water line under the sink and the fill line for the fresh water tank. I mounted the valve on the side of the bathroom vanity. Opening the valve causes the pump to run and water to recirculate back into the tank. This serves two purposes. First, it lets us get the water in the lines hot before turning on the sink or shower tap. Therefore we do not waste any water waiting for it to get hot. Second, if I want to take a Navy shower I just leave the recirculation on. The hot water being made while I am soaping up just flows back into the tank and the lines still have hot water in them when I turn the shower back on since the burner is still firing. This has worked very well."

I actually was toying with doing something similar for a different reason - freeze protection for the main water tank. It wouldn't be to hard to make a recirculating system for cold weather that was fully automated.... Just running at short intervals to boost the water tank temp based on temp probes.

[CA_Tallguy]

Actually, I am trying to do mostly boondocking. So maybe I've made a mistake going tankless but as per my last post there could be some solutions or if it really stinks then it won't be the end of the world to switch back to conventional.

[Alumaholic]

Originally Posted by CA_Tallguy

Actually, I am trying to do mostly boondocking. So maybe I've made a mistake going tankless but as per my last post there could be some solutions or if it really stinks then it won't be the end of the world to switch back to conventional.

Since you are an extremely capable person, I am confident that you will come up with an innovative solution that works for you and that you will be able to fabricate and install the solution yourself.
I am more concerned for the less handy Airstreamers who must pay someone else for repairs, replacements, upgrades, etc.
It seems important to use these threads to get this information out there, especially in these times when so much is done in the name of "saving the environment" without full consideration of the unintended consequences.
The Atwood RV 6 to 10 gallon water heaters are so great for the Airstream application, they can scarcely been improved on.
As for your thoughts on recirculating the water in the fresh-water holding tank, you will probably never need to do that unless you intend to spend day after day with day-time temps below freezing. A full fresh-water holding tank has enough thermal mass to keep it from freezing if you are keeping the coach warm enough to live in.
Check with "Deauxrite" who is living on the South Rim of the Grand Canyon as we speak.
All the best!

[bredlo]

Part of the reason I'm interested in tankless is size, and the ability to vent out the bottom; the RV-550 NSP offers advantages in both these areas... giving us additional flexibility when laying out the appliances in our '57 gut rehab.

Good point about the difficulty with Navy showers, though. We like to be green, but understand there are always trade-offs as well.

[Alumaholic]

Originally Posted by bredlo

Part of the reason I'm interested in tankless is size, and the ability to vent out the bottom; the RV-550 NSP offers advantages in both these areas... giving us additional flexibility when laying out the appliances in our '57 gut rehab.

Now I understand. It makes more sense as a design consideration than an environmental one. Thanks!

[CA_Tallguy]

I chose it without environmental concerns being top on the list. I am more interested in the technology and I like that it is instant. Call me lazy or a brat, but I don't like having to wait for things and want to shower or wash dishes at the moment I'm ready. Also, the more I think about it, I'd rather fill and dump water more often than spend money refilling propane (though I understand the savings isn't all that great). And while I do boondock a lot, I'm generally on the move every few days so a little more dumping and refilling water tank shouldn't be too bad. And from what I read others saying, long showers while hooked up are the real luxury.