Water heater anode rods

By: Peter Quilty, Photography by: Peter Quilty


Water heater anode rods are essential consumables that will extend the life of your HWS, if they’re regularly replaced.

RV-repair -centre

The sacrificial magnesium anode rod equalises aggressive water action providing cathodic protection for the water heater tank.

In other words, an anode rod absorbs the corrosive action caused by hot water and prolongs the life of your water heater tank.

The anode rod is a very important factor in tank life and should only be removed for inspection or draining.

Replacement of the anode rod is recommended when consumption or weight loss is greater than 75 per cent.

With regular inspection and replacement of the anode rod, tank life can be greatly extended. Frequency of anode replacement will vary depending on the water conditions and usage.

In most conditions, anode rods should last at least one year. If your magnesium anode rod does not last for one year, you may want to use an aluminium anode rod.

Aluminium rods react slower and should be used only in situations where magnesium anode rods do not last one year.

Check the anode rod every time you drain your water heater. The anode rod can be located by opening the water heater’s exterior access door. It is positioned in the bottom centre of the water heater housing.

Unscrew the anode rod to drain the tank. If the rod is mostly eaten away, replace with a new one.

And always keep a spare in your caravan or RV.

Please note: Operating the water heater without the anode rod voids the manufacturer’s limited warranty and shortens the tank life.

NB. These images and step-by-step instructions depict the simplicity of replacing a Suburban magnesium anode rod performed by The RV Repair Centre foreman, Paul Hewat, in Bayswater (Vic).

STEP 1

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Checking and ultimately replacing an RV Hot Water Service (HWS) anode requires a few tools from your DIY tool shed. The length of garden hose has a reducer on the end to flush the HWS tank when the anode is removed.

REMEMBER: Flush the HWS Tank with pressured clean water after the anode is removed to remove scale and residue.

STEP 2

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A typical gas/electric storage tank hot water service located on the side of an RV with its cover open, exposes the controls and anode. The anode is located centrally at the bottom of the HWS hidden partially behind the gas pilot light tube, in this image.

STEP 3

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Before attempting to work on the HWS, ensure it is turned off and that the LP Gas bottle(s) are off and 240V mains power is disconnected from the RV. This image is checking that the LP Gas pilot light is off.

REMEMBER: Also ensure the HWS water temperature is cool before attempting this procedure.  

STEP 4

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Relieve any pressure within the HWS system by releasing the protection valve. Water may drain from the red hose during this process. Wait for all water pressure to subside before returning the valve back to its normal position.

STEP 5

Clean the area around the vicinity and use a 1 1/16 inch socket extension bar and ratchet in readiness to remove the sacrificial anode.

STEP 6

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Ensure the socket is firmly attached to the anode. Unscrew anticlockwise slowly.

STEP 7

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With the sacrificial anode removed, we see it’s timely that the owner of this RV had it checked, otherwise corrosion to the HWS 240V element and tank would have occurred.

TOP TIP: It’s advisable to check the condition of the anode regularly as water condition varies considerably.

STEP 8

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Use a garden hose with good pressure to flush out the HWS storage tank. As most of the residue is located at the bottom of the storage tank, repeat the flushing process a few times or until clean water flows out.

TOP TIP: Just flush a few litres at a time to save on water.

STEP 9

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With the HWS storage tank flushed, it’s time to install a new anode. It’s always good practice to clean the thread that supports the anode within the HWS before installing the new unit.

REMEMBER: Place plumbers tape around the thread of the anode to avoid leakage.

STEP 10

Place the new anode into the HWS and turn by hand clockwise, before using the socket.

STEP 11

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Use the socket to tighten the anode into position.

REMEMBER: Do not over tighten.

STEP 12

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With the new anode snug within the HWS storage tank, it’s time to hook up the mains pressure water to the RV and purge the system from air, and also check for water leaks around the anode.

STEP 13

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Purge air from the system by turning on an HWS tap inside the RV.

TOP TIP: It may take a few minutes to purge the air from the system.

The full feature appeared in Caravan World #575. Subscribe today for the latest caravan reviews and news every month!