To Drain or not to Drain...

[tlmgcamp]

My water heater is of the type that uses an anode. We are pre-retirement so we only get out a few times per year. My question is if I should be leaving the tank full between trips or empty it.

During its first dewinterizing last month, the tank was empty. After flushing the pink from the lines, I filled the tank then drained it just to flush it out. I noted clumps of a white to white/gray substance coming out with the flush. Was this remnants of the anode at work or something else? Heater worked fine this weekend

 

[Mountain high]

Got a large thick clump of white to white/gray substance dumped into a cup of coffee from an old vending machine at work. I didn't drink it to determine what it was. It was supposed to have been cream. I threw it out. So I drain our tanks including the water heater between trips. Nasty fungus stuff grows in a sitting water heater during hot temperatures.

 

[john & Piper]

Living in LA (lower Alabama) I always dump my water heater due to the heat and humidity. No idea what the white stuff was, but never had it in our camper.

 

[Kirk]

I noted clumps of a white to white/gray substance coming out with the flush. Was this remnants of the anode at work or something else?

The anode has nothing to do with the white mineral as it is calcium that precipitates out of the water when it is heated. That same thing develops in a home water heater and even a teakettle that is used a lot. Another place that it is commonly found is in a humidifier if used in a house. You should drain any water heater at least once a year, especially if you are where you have hard water. I also do a flush with white vinegar occasionally too.

How to Save Your Water Heater from Death by Calcium Buildup​

 

[Professor David]

I noted clumps of a white to white/gray substance coming out with the flush

Both Kirk and Western slope are potentially correct. More information needed...Was the white/grey stuff hard/flaky (mineral deposits)... or...soft/slimy (fungus)?

 

[tlmgcamp]

Both Kirk and Western slope are potentially correct. More information needed...Was the white/grey stuff hard/flaky (mineral deposits)... or...soft/slimy (fungus)?

I wouldn't say slimy. Best description that I can offer is when a powder cakes up when it gets wet. Kicking myself for not taking a picture

 

[sonox]

I also believe it to be calcium. When was the last time you changed your anode rod?

 

[Professor David]

powder cakes up when it gets wet

Sounds like minerals including calcium. Have you done the vinegar treatment lately? check out this video. The guys show mineral deposits coming out when he flushes his water heater...might look familiar to you.

 

[BoomerTX]

As a follow up question, if in between trips, (maybe just couple of weeks) if you drain the low point valves does this get rid of the water in the water heater or is there still a need to remove the anode?

 

[FunSteak]

I drain our WH every winter, and replace the anode in the spring. At that time, I also flush it with one of those wand things on the garden hose. A large amount of the white stuff referenced above comes out every time. I assumed it was from the anode rod, as it's a toothpick every fall.

Some think it could be calcium? We have good, fairly soft water at our home, which is where I fill our tank 98% of the time, and have never noticed any calcium issues anywhere else.

 

[tlmgcamp]

I also believe it to be calcium. When was the last time you changed your anode rod?

Ano

Sounds like minerals including calcium. Have you done the vinegar treatment lately? check out this video. The guys show mineral deposits coming out when he flushes his water heater...might look familiar to you.

That looks like the white stuff. Thanks.

 

[tlmgcamp]

I also believe it to be calcium. When was the last time you changed your anode rod?

The anode is about 3/4" diameter so I believe it has some life left. But that was the second part of my question: should I leave the hot water tank full when not using the RV? If yes, the anode will continue to sacrifice itself. If no, then the anode is preserved, but are there other unanticipated consequences??

 

[Professor David]

I drain our WH every winter, and replace the anode in the spring. At that time, I also flush it with one of those wand things on the garden hose. A large amount of the white stuff referenced above comes out every time. I assumed it was from the anode rod, as it's a toothpick every fall.

Some think it could be calcium? We have good, fairly soft water at our home, which is where I fill our tank 98% of the time, and have never noticed any calcium issues anywhere else.

I have an Atwood water heater with an aluminum tank that doesn't require an anode...I still get the mineral deposits especially after the vinegar treatment. In the video I posted above, the guy has a water softener on his RV and still gets the mineral deposits. Seems like a water softener doesn't completely take care (though probably helps a lot) of this issue of mineral precipitation under the conditions of an RV water heater.

 

[Ex-Calif]

Hmmm... Calcium builds up on aluminum pretty readily. When you drain it, the calcium dries and flakes off all at once vs. over time during water flow. Kind of like Schrodinger's cat if you never drain, you'll never see the calcium flakes until they clog the aerators in the faucet heads.

The anode won't fix calcium deposits and are intended to be sacrificial. Two metals in contact via a conductor (water) will create a very small voltage and the weaker material will erode away as part of the reaction. Anodes are usually weaker than aluminum and are designed to take the hit of erosion.

Nothing wrong with emptying the tank in the winter - stops the anode/cathode reaction and saves your anode some wear. Then flush when you refill. I do that any time the tank is emptied. Set the pop-off valve open, run the city water until water flow out the top. Close city water and pull tank drain.

My RV is always on city water and basically always occupied so my tanks rarely get drained. If I get a squawk of weird tasting water then I drain and sanitize everything. I leave the house tank about 1/2 full and periodically run the pump to sample the water taste.

 

[Tulecreeper]

I drain our WH every winter, and replace the anode in the spring. At that time, I also flush it with one of those wand things on the garden hose. A large amount of the white stuff referenced above comes out every time. I assumed it was from the anode rod, as it's a toothpick every fall.

Some think it could be calcium? We have good, fairly soft water at our home, which is where I fill our tank 98% of the time, and have never noticed any calcium issues anywhere else.

Wow, an anode in your water heater should last 3 - 5 years depending on how much water moves through the system. I cannot imagine what would cause yours to wear away so quickly.

 

[Kirk]

Best description that I can offer is when a powder cakes up when it gets wet.

It is the normal calcium which builds up in all water heaters, the rate depending on how hard the water is.

As a follow up question, if in between trips, (maybe just couple of weeks) if you drain the low point valves does this get rid of the water in the water heater or is there still a need to remove the anode?

my question: should I leave the hot water tank full when not using the RV?

That depends on how long you will be and the quality of the water. Hard water will have some effect on the anode but little unless you have really hard water but there is a possibility of algae growth starting. I don't drain mine unless the RV will sit unused for a month or longer.

 

[FunSteak]

Wow, an anode in your water heater should last 3 - 5 years depending on how much water moves through the system. I cannot imagine what would cause yours to wear away so quickly.

Interesting. At the end of every season, mine looks like the 75% image in Kirk's post above. Might I have a problem here??

 

[DutchmenSport]

As a follow up question, if in between trips, (maybe just couple of weeks) if you drain the low point valves does this get rid of the water in the water heater or is there still a need to remove the anode?

Your water heater fills from the bottom. Under pressure, the hot water leave the tank from the top. So, if you simply open the hot water low point drain, no... the tank will never empty as the "outlet" of the tank is at the top.

If you open the low point drain, it won't drain anything either, unless you open cold faucet, or all the cold faucets. Otherwise, the lines are in a vacuum and will never drain. The water heater will never drain either unless the hot water faucets are opened also.

Now, depending on your unique camper (none are the same, even with the same model number), it's possible the low point drain will not actually drain the water from the hot water tank.

Your best bet to drain the water heater is to pull the drain plug or anode rod. That way, you know it's empty.

Here's a tip. If you pull the anode rod, after it drains, insert the anode back into the tank and finger tighten it. You don't need to "wrench" tighten it back up. Finger tight is good enough. Just make sure you insert the anode back in. Why? Because, if you leave the anode out, the threads of the tank AND the threads of the anode rod will rust up.... fast.... and real bad ... making it near impossible to insert again.

One more comment...

In the past, I use to empty my fresh water tank, and my water heater tank every time the camper moved. That meant, draining everything from home to campsite #1. Then campsite #1 to campsite #2. Then campsite #2 to home again.

I did this on 3 different travel trailers.

When we got our fifth wheel, I quite draining the water heater and I now always leave at least, a few gallons of water in the fresh water tank.

We use our fifth wheel much, much more than we ever used travel trailers, so draining the water heater is not so practical any more. Plus the extra weight for water in the fifth wheel doesn't affect the "feel" of the tow, like it profoundly did in all my previous travel trailers.

Once the fifth wheel is at home, we still use the camper 24x7 full time. So, draining just makes no sense now.

Of course, for winterizing, everything is drained completely. I did change the anode rod this year (after almost 5 years of use on the same one... and it still had at least 50% life left). When I inserted the new one, I didn't use Teflon on the threads, and I noticed a small drip, causing the water pump to kick on and sputter occasionally.

So, just a couple days ago, after returning home from a 2 week "outing" I decided to go ahead and put the Teflon on the threads. When I pulled the rod out, I noticed it had a slight slimy coating on it. Mostly, the rod is dried out, even wet, even chalky. So, this is a first.

As we are home right now (for the next 3 weeks before heading out for the next 2 and 1/2 months (End of June, July, August, and part of September), I'll go ahead and re-sanatize the water heater and try to clean it out real good. I think the slimy texture might be the start of something growing, I don't want in there.

Maybe I should drain it more often! (That's my point).

So, anyway, there's my story.

 

[Gary RV_Wizard]

My water heater is of the type that uses an anode. We are pre-retirement so we only get out a few times per year. My question is if I should be leaving the tank full between trips or empty it.

During its first dewinterizing last month, the tank was empty. After flushing the pink from the lines, I filled the tank then drained it just to flush it out. I noted clumps of a white to white/gray substance coming out with the flush. Was this remnants of the anode at work or something else? Heater worked fine this weekend

The white/gray stuff is just mineral salts that get precipitated out of the water when heated. Most likely some form of lime (calcium carbonate). It's a normal residue in many parts of the country and happens whether or not an anode is in use. Atwood/Dometic heaters that do not use anodes still get the whitish salts in the bottom of the tank if the water source is "hard", i.e.contains minerals of various sorts.

The anode literally gets eaten away as it gives up its electrons to neutralize metals in the water that would otherwise attack (corrode) the tank walls and internal components. Sometimes a tiny piece of anode breaks off and falls to the bottom of the tank, but that's random chance rather than something you expect to see all the time.

 

[blw2]

As a follow up question, if in between trips, (maybe just couple of weeks) if you drain the low point valves does this get rid of the water in the water heater or is there still a need to remove the anode?

dutchman sport beat me to the answer.....
the only thing I'll add....as food for thought.... in my rig, the outdoor shower is mounted close to and just lower than the water heater. I can drain the heater by opening the hot water on the shower and cracking open the T&P valve to vent the tank. The hot water outlet is about the same level as the drain (same height on the tank) so I recon it's about the same result....