Wednesday, July 4, 2012

Flushing the Hot Water Tank

The Roadtrek has a propane hot water heater to heat your hot water and a six gallon hot water tank to hold that water and keep it hot. Inside you can see the tank inside one of your cabinets - mine is in the first cabinet on the driver's side under the bed. You will know it is your hot water tank because it is covered in white foam. This is the tank from the inside of the Roadtrek. The hot water heater and tank are actually accessed from the outside of the Roadtrek on the driver's side.

In the middle of the driver's side of the outside of the Roadtrek you will see a panel with a mesh screen in the upper right corner and vents next to that. In between the screen and the vents there is a little ring. The ring is the latch that holds this panel tight to the body of the Roadtrek. By flipping that ring up and turning it so that the ring is vertical, the panel can be pulled out from the top edge and the ring will slip through a slot that is behind it. When you open this panel, put the door in a safe place. You have now accessed the water heater and the water tank.

What you see in the photo above is the hot water heater and behind that is the tank that you saw inside. You can access the heating element and the interior of the hot water tank through this panel compartment.

You can access the heating element and the interior of the hot water tank from this access panel compartment. Here you will find access to the heating element and at the bottom, right in the
middle - the anode rod which also serves as the plug for the hot water tank. You can see it in the photo - it is what looks like the top of a hex head bolt.

Roadtrek installs a SUBURBAN hot water heater. I capitalized Suburban to emphasize that this is important to know. There are, from what I have learned, two types of hot water heaters for RVs, named for their manufacturers - Suburban and Atwood. They are different in what they are made of and they take different Anode Rods. It is important to check the anode rod at least twice a year - though the manual says four times a year - and that would not be a bad idea.

It is the job of the anode rod to corrode and it does this to prevent your hot water tank from corroding. Don't ask me how it does this - but it has something to do with a slight electric charge that passes through the rod and attracts the minerals in the water that would damage the walls of your tank - instead of damage to the walls, the rod self-destructs. How nice of it! Each time you check the rod, it will be getting thinner and thinner. It must be replaced when it has corroded 75% - I am told this is about the diameter of a pencil.

To remove the rod - just like when winterizing - you use a ratchet wrench and a one and 1/16 inch socket. Unscrew the head of the rod and it will loosen just like a bolt. When it is out of the threads, pull it out by the head and a long rod will come out, along with a lot of water. BUT WAIT! FIRST MAKE SURE YOUR HOT WATER HEATER IS TURNED OFF. THEN - Never start to remove this rod with the water heater still hot or with hot water in the tank. Let the water heater and the water cool down to cold. THEN before touching the anode rod head to unscrew it, pull the pressure release handle at the top of this compartment. It is a little pull handle connected to a water faucet. Pull that handle up and step back - water will come rushing out of that faucet and this is water under pressure. When no more water is coming out, that is when you take your ratchet wrench and socket and start to unscrew the anode rod. Again, when that rod is out, a great deal of water - up to six gallons of water will come rushing out. As the rod gets loose, step aside. Many have experienced the remaining pressure in the tank shoot that rod past them!

Once the rod is out, you are draining the hot water tank. Place the rod on something clean. Despite how it looks, this is in your clean hot water which will go on you and possibly into your mouth. So, put it in a zip lock bag or someplace clean until you are ready to put it back into the tank. Water will continue to flow out of the hole where the rod used to be. When the water stops there will still be some water in the bottom of the tank. If you are just checking the rod, or you are winterizing, this little amount of water does not mater.

But hey, the title of this article is "Flushing the Hot Water Tank". Have you flushed the tank yet? No.

As the anode rod corrodes it leaves behind sediment and large white and grey flakes of minerals, etc. in the water and this settles to the bottom of the hot water tank. It is important that twice a year you flush these out - or you will discover that by some magic they will find their way into your hot and cold water lines. Don't ask me how the hot and cold water lines can cross but the Roadtrek specialist at dealer service told me that somehow they do. I found this out the hard way when I saw these particles coming into the toilet when the toilet was flushed. And then we checked the sink (without the filter on) and found grit coming out of there too. This was the other problem that I mentioned in a recent article that we took to dealer service. The fix is to flush the hot water tanks.

On a previous trip, I had purchased from the dealer's RV supply shop a gizmo called the Tank Saver. This is a thin plastic wand with a bent tip that attaches to a hose and is used to clean out and flush the hot water tank. How prophetic of me to think to buy this before I needed it! It has a valve on the end to turn on and turn off the water. It acts like a little pressure washer to agitate all of the sediment in the bottom of your hot water tank and flow it out of the drain hole as the water that you are shooting into the tank comes rushing out.

I connected this to a fresh water hose. You want to use a fresh water hose because you are putting water into a fresh water tank (the hot water tank is a fresh water tank). I turned the water on the house outside faucet to full. I put the wand into the tank and I turned the valve on the bottom to on and water shot into the tank. Moving the wand all around the tank, I immediately saw large chunks of sediment - some over two inches - rush out the drain hole with the water. The instructions for the Tank Saver say it only needs two minutes to clean the tank. I stayed at it more than ten minutes - until I saw nothing more coming out with the water and the water was clean. On my driveway under the hot water tank, there was a pile of sediment and large chunks that were white and grey. The tank was thoroughly flushed.

Before screwing the anode rod back in, it is recommended that you put Teflon pipe tape around the screw threads of the rod so that the rod will not get stuck in the tank. Wrap some pipe tape around the threads and put the rod back in the drain hole. Screw it in with your fingers and then use the ratchet wrench and socket to get it in and tighten it down. You do not want this to leak. Fill the tank with water and check for leaks outside at the anode rod head.

It is recommended that you flush the tanks at least TWICE a season.

Above is a picture of a new anode rod for a Suburban hot water heater. The Suburban rod is longer than the Atwood rod. It is made of either magnesium or aluminum. I am told that the one that comes in the hot water heater is magnesium. The magnesium rod and the aluminum rod are both supposed to work the same. Of course, the paper and the rubber band come off before it goes into the hot water heater. You can purchase these at any RV supply shop. This one came from the shop at my Roadtrek dealer. It is something that you should buy in advance and keep a spare to save a trip to find one when you need to change the one in your hot water tank.


  1. Just a small correction to your article. The Atwood water heaters do not have an anode rod.
    Not needed because they are made of a different metal than the Suburban

    1. I have seen in RV stores short anode rods labeled for Atwood hot water heaters.

  2. i have read here and there about filling the water heater with vinegar to clean out the sediment. have you done this ? if so how do you get the vinegar in

    1. I have never used vinegar or put anything into the hot water tank except the bleach/water mixture to sanitize all tanks including the hot water tank and then after that just water. There is no need. The Suburban hot water tank is glass lined. Any sediment in the tank will fall to the bottom of the tank in the water and when you open the hex nut and pull out the anode rod, you will see most of the sediment fall out with the water. If you are who posted this on the forum and I responded to with this link, you are de-winterizing. Mostly you will see this sediment come out in the Fall when you drain the hot water tank to winterize. When you dewinterize - see all of my articles on dewinterizing - look on the how to page of this site for links and it will tell you what to do. If you are going to flush the tank during the dewinterizing process do it before opening the hot water heater bypass valves - leave it in bypass - take out the anode rod on what should be an empty tank, use the flush wand as shown in this article and if there is any remaining sediment in the tank it will be "pressure" washed out - the water comes out from the wand just connected to a fresh water hose with a lot of pressure. Just run the wand - as described in this article around the tank - especially all over the bottom of the tank. You will see some sediment wash out of the drain hole and over the side of the van to the ground. When you see nothing else coming out - it is obvious as the sediment is white and black granules, some like little gravel coming out with the water and all over the floor - then put the anode rod back into the drain hole, wrap the screw threads on the rod with plumbing tape first, and then tighten it down with your ratchet wrench and correct size ratchet. It never goes in all the way down and about an 1/8" or so of thread and white tape will show on the outside. This is not a problem. Next, open the hot water bypass valves and add your bleach/water mix to the fresh tank and follow my instructions - in my articles on dewinterizing and sanitizing - to get the bleach in and what to do once it is in. This year once the bleach was ready to come out since it will not all come out of the hot water tank, AFTER going through all of my steps to get the bleach water out of the pipes and plumbing, I drained the fresh water tank at its low point drain of bleach water, I connected a city water hose to the Roadtrek, turned on the hose and opened the outside hot water faucet. No other faucet. This will run all of the bleach water that is inside the hot water tank out and through the outside shower hot water faucet. If you see my current article you will see that the hot water tank never empties unless you take out the anode rod. It refills with new water as soon as any water comes out of a hot water tap. So, by running fresh water into the tank with the outside shower faucet on. Ran the water through for ten minutes - it filled and flushed the six gallon hot water tank in that time a few times. After that there is no bleach smell in the water coming out of the hot water tank. If you want to do a test to see, take a paper cup after ten minutes and put it under the outside shower connection and smell the water coming out. It should no longer have any bleach odor. That is it. Your hot water tank is clean, sanitized, and ready to use. Follow the steps in my sanitizing articles and you will be good to go! I am not even going to suggest a way to get vinegar in the hot water tank - you will be smelling vinegar in the water for a long time. If you really want to know email me with the email us link in the right column on the side if this page.

  3. how do you shut off the hot water? there is a terrible mold smell coming from this compartment and I have only owned this 4 months thanks

    1. I have just answered your question on the other post you aske about this on. TO shut off the hot water - first do what this article says. Then go inside and in that cabinet turn the hot water bypass valves to prevent water from going in or out of the hot water tank. See my winterizing article on how to do this. Now water will not go into the hot water tank and it will remain empty (there will be a small amount of water left on the bottom of the tank below the level of the drain hole. You can try leaving the anode rod out and leave the drain open for a couple of weeks for air to dry out the remaining water, or get a small nozzle attachment for a wet/dry shop vac and suck the rest of the water out - putting the small nozzle inside on the bottom of the tank - BUT if you close up the tank condensation will put some water back inside. If you leave the drain hole open you stand the chance of bugs or mice going inside, do don't do that. If you drain your hot water tank and bypass it, NEVER turn on the hot water heater switch or you will have a fire. In my Roadtrek on the front of the side wall on the kitchen side at the top edge there is a small circuit board with wires going into it. If you gently pull the wire connection up a small connection card with the wires attached should slide out and disable the wall switch. As I said in my other answer. You have a big problem with mold in that cabinet and it needs to be professionally dealt with.

  4. I just bought a used 2004 190P and the anode rod is missing and the threaded hole is open and has some rust, due to being driven on salty roads for a short period before the purchase.

    1) is there potential that the water tank has been damaged because the hole was left open?
    2) Can I screw some kind of temporary plug into until I get a replacement anode?
    3) Are new anodes available online?

    Thank you!!

    1. It is unlikely that the tank has been damaged inside. The tank is glass lined. It is common to see rust on the threads of the drain hole. You could take a toothbrush and brush that out - toward the outside of the hole - not into the tank. The problem with screwing in a temporary plug is making sure you match the threads. If you strip that hole that is trouble you don't want. It is not uncommon for RVers to leave that hole open for a period of time to allow the tank to dry out - and when winterized. The Roadtrek Hot Water Heater is a Suburban Hot Water Heater. The anode rod must be specific to Suburban. It is a long rod (another hot water heater company uses a short rod - less than 6"). They are made in Magnesium or Aluminum - your choice - it comes from Suburban with a magnesium rod. Several companies make rods for our hot water heater - as long as it is marked for Suburban it will fit. When putting it in, put plumbers tape around the threads, you will need a specific size socket and a socket wrench to put it in and take it out. It is not a usual size the comes with basic sets - it needs a 1 and 1/16 inch socket. You may also need an extender to be able to turn the wrench without hitting anything - or get a deep well socket for the added length. Some of the threads on the anode rod will stick out when the rod is screwed in fully - once it stops turning don't force it. It is normal for it it to stick out some. You can buy this anode rod anywhere that sells RV or Travel Trailer accessories and parts. They are available online. If there is an RV shop anywhere near you they should sell it. This Suburban anode rod is used in many RVs not just Roadtreks. Camping World should have it. Other RV supply websites - even Amazon should have it.