DIY: Extend your Caravan Hot Water Service Life
A quick rundown on Hot Water Service Maintenance for your caravan. Partnered with The RV Repair Centre.
Many caravans in Australia are fitted with a hot water service such as a Suburban branded unit. They have steel tanks which are prone to corrosion but are protected by a clever gadget. A rod made out of magnesium, known as an anode, is fitted inside the tank. It corrodes more easily and ‘sacrifices’ itself, minimising steel corrosion. Once the anode is corroded, the steel parts will begin to corrode more rapidly, shortening the life of the hot water service. Fortunately, the sacrificial anode is relatively inexpensive and simple to replace.
The anode needs to be removed from the tank periodically for physical inspection. Suburban advise that when the anode has reduced to around half of its original diameter it is time to replace it. A new Suburban anode is about 17mm, so it is past its useful life at around 9mm. The example photographed below has corroded to well below that.
Below are the steps to remove and replace the anode and to also flush out built up sediment.
Step 1
Turn off and disconnect everything: shut off electrical power and gas supply, turn off the hot water service, turn off the water pump, and disconnect mains water. Allow time for water inside the hot water service to cool.
Step 2
Operate the pressure relief valve to prevent water spurting out when the anode is removed.
Step 3
Check that the hot water service compartment has adequate sealing to prevent water leaking inside the van.
Step 4
Identify the anode.
Step 5
Unscrew and remove the anode. Be aware that water will flow out quickly.
Step 6
Operate the pressure relief valve again to make it easier for water to flow out of the HWS tank.
Step 7
You may see signs of sediment in the tank flushing out.
Step 8
Flush the tank by inserting a hose fitting inside the anode opening. Let the water flow for a couple of minutes. (Note all the sediment pictured.) A fitting that creates a jet that squirts up will be more effective. You could use a home garden irrigation nozzle. If you can’t rig something up just a plain hose end will do the job.
Step 9
Move the fitting around inside the tank gently to flush out more sediment. Be aware there is an electrical element inside so do not push too hard.
Step 10
It is now time to fit a new anode. Note how corroded the original is.
Step 11
Apply thread sealing tape to the anode thread.
Step 12
Insert the new anode into the opening and start the thread by hand to avoid cross threading.
Step 13
Tighten the anode gently to create a seal.
Step 14
Refill the tank with water.
Step 15
Turn the pump back on and run the hot water tap to purge air from the system.
Step 16
Operate the pressure relief valve again to assist purging air.
Step 17
Check the anode seal is not leaking.
If in doubt, consult a professional
Improper maintenance could lead to injury, death or property damage. Maintenance work of this nature should only be undertaken by persons with suitable mechanical competence. Information provided is general in nature, not comprehensive and can only be taken as a guide. Individual discretion must be exercised and persons undertaking described tasks do so completely at their own risk. Publishers and creators of this content accept no responsibility for loss or damage.
Thanks to Andrew Phillips and the team from the RV Repair Centre, 120 Canterbury Rd
Bayswater Nth Vic 3151, Ph: (03) 9761 4189