Need help choosing water heater...

When I replaced my attwood I believe it came with a new switch panel. It has 2 rocker switches. Propane or 120. If you just have propane it will be the same style plate with one switch. My rig has a dedicated breaker for the WH that runs over to a wall switch before going to the water heater. So the 120 volt wall switch has to be on then the small rocker switch would tell the control board to run on electric. WH also has 12 volts going to it. Rocker switch turns it on and off. Some people like to be able to use electric when they are not paying for electric and save propane.

If I recall there is a block of wood maybe 3/4 thick under mine that may support it. I'd have to look at it again but someone else may be more familiar. It's probably mentioned in the install instructions.

I paid $350 for mine on ebay with 120 volt option too.

The atwood does not require an anoid rod so you wouldn't ever have to worry about replacing that. We are in a notorhome and the water heater will operate on either electric or propane. Inside there is a switch like a light switch to turn on the electric and another if we want it on propane. We have a 10 gallon ( I wouldn't get smaller) and can both take showers without running out of hot water. You can operate it on both electric and propane at one time for faster recovery, but we have not found that necessary. We are usually someplace with hookups and are full-time. We leave it on 24/7 on electric. Only time not on is when we are going down the road. As far as we know, the one in our unit is 16 years old and still going strong.

BradKW wrote:
Hello! I'm building a DIY RV from a box truck platform and I've decided to go with a 6 gal RV-style heater instead of tankless on demand. At least I think I've decided that. I have narrowed it down to these two...both are 6 gal, propane with DSI (direct spark ignition).

Oh, one question I can't find in specs...on these units, you ignite with the switch, but then what turns the heater off so it doesn't just sit and heat water for hours?
Both Brands use 'set of thermostats' to turn on/off

Atwood uses a 140*F t-stat for routine operation and a 180*F high t-stat (ECO---Energy Cut OFF) to shut down heating IF normal t-stat fails.
Atwood also uses a 'thermal fuse' to shut down propane flame should it blow back out of combustion chamber due to obstructions ---one time device set for 190*F

Suburban uses a 130*F t-stat with a 180*F high temp t-stat.
Suburban does NOT use the 'thermal fuse' blow back protection device.

I've never so much as touched an RV heater before, so any input welcome...and it's not like those 2 choices are anything more than the result of a few nights googling + Amazoning, so open to other choices...

Thanks!

Suburban uses a STEEL tank......glass-lined so an anode rod has to be used. If tank leaks etc---have to replace whole water heater (no replacement tanks
High temp t-stat has manual reset if it trips.

Atwood uses an ALUMINUM ALLOY tank so no anode rod needed. Tank can be welded or replaced if it should leak. Swap parts.
High temp t-stat will auto reset once water cools off

Why just 6 gallon and not go higher capacity......10 gallon?
Why propane ONLY...never going to be hooked up to AC Shore power?


Both gas only water heaters are just 12V DC systems......main feeder FUSE (7.5A fuse is sufficient), a DC ON/OFF Switch with indicator light and 18 ga. wire

Old-Biscuit wrote:

BradKW wrote:
Hello! I'm building a DIY RV from a box truck platform and I've decided to go with a 6 gal RV-style heater instead of tankless on demand. At least I think I've decided that. I have narrowed it down to these two...both are 6 gal, propane with DSI (direct spark ignition).

Oh, one question I can't find in specs...on these units, you ignite with the switch, but then what turns the heater off so it doesn't just sit and heat water for hours?
Both Brands use 'set of thermostats' to turn on/off

Atwood uses a 140*F t-stat for routine operation and a 180*F high t-stat (ECO---Energy Cut OFF) to shut down heating IF normal t-stat fails.
Atwood also uses a 'thermal fuse' to shut down propane flame should it blow back out of combustion chamber due to obstructions ---one time device set for 190*F

Suburban uses a 130*F t-stat with a 180*F high temp t-stat.
Suburban does NOT use the 'thermal fuse' blow back protection device.

I've never so much as touched an RV heater before, so any input welcome...and it's not like those 2 choices are anything more than the result of a few nights googling + Amazoning, so open to other choices...

Thanks!

Suburban uses a STEEL tank......glass-lined so an anode rod has to be used. If tank leaks etc---have to replace whole water heater (no replacement tanks
High temp t-stat has manual reset if it trips.

Atwood uses an ALUMINUM ALLOY tank so no anode rod needed. Tank can be welded or replaced if it should leak. Swap parts.
High temp t-stat will auto reset once water cools off

Why just 6 gallon and not go higher capacity......10 gallon?
Why propane ONLY...never going to be hooked up to AC Shore power?


Both gas only water heaters are just 12V DC systems......main feeder FUSE (7.5A fuse is sufficient), a DC ON/OFF Switch with indicator light and 18 ga. wire

Thanks for the detailed information!

I figured 6 gal would be good because space is tight and that seems like a sufficient amount to take a shower and/or do dishes...and propane-only because I've been told that these type of units are very efficient and just sip propane. Combined with being "one less thing" to wire into a 1k watt solar off-grid system that I'm finding a bit overwhelming already, and...

Do any of these units have adjustable t-stats, or is mixing cold water in to get right temp always a part of the equation?

We have always had a Dometic water heater. As far as I know they do not sell them with adjustable thermostats. Looks like you are able to purchase one in aftermarket. The procedure is to carefully turn on hot water and then adjust cold water and hot to desired temp.

The reason I say carefully is because that water comes out HOT - regardless of what the thermostat is set for.
The thermostats are just small button like affairs that attach to the outside of the tank.
Barney

I find the best way is to mix the cold with the hot. Been doing it that way for 11 years.
Works good.

Hi,

They do NOT sip propane. I would recommend a ten gallon unit with electric. I find that I can turn on the heater first thing in the morning--get washed up and then turn it off and it "coasts" for the rest of the day with enough heated water for the supper dishes. In my previous RV with a 6 gallon tank--I would run out of hot water and have to turn it on a 2nd time.

There are some that have a "motor assist" coil where heat from the engine is used to heat up the water in the tank. If mine fails, I'll try to find one of those units.

Here's a new option for RVs
https://www.truma.com/us/en/home/index.php

The folks at www.rv-dreams.com recently added one and so far are pleased with it.

Another option- albeit a pretty pricey one, but gives you LP or electric fired hot water plus hydronic heating Twin Temp Jr.

Atwood has an 'adjustable' aftermarket optional t-stat that replaces the normal temp t-stat. (110*F---150*F VS the fixed 140*F)

The 10 gallon is just slightly larger then 6 gallon

6 gallon.........16" W x 12.5" H x 18" D
10 gallon........16" W x 15.5" H x 21" D

A 'motor assist' option is a aluminum tube welded to tank-----coolant lines from/to engine allows water in tank to be heated while driving.

Atwood Models----see pg. 4 of brochure
LINK