Are all hot water heaters the same?

Not all caravans, campervans or RVs come with a hot water system/hot water heater.  If the caravan, travel trailer, campervan or RV does not have a hot water heater then you need to boil the jug (electricity) or kettle (gas) for washing up and showering.

There are two main types of hot water heaters ie: storage and continuous or tankless.  Storage hot water systems hold hot water in a tank where continuous (or instant/tankless) systems heat the water as it passes through a heater.  The hot water heater storage tanks are available in various sizes.

Most RV’s have the storage type hot water heater.  These storage type hot water heaters operate on mains power or LPG gas.  If operating on gas, you must remove the gas cover or cowl located on the outside of some of the earlier model RV’s prior to switching the gas unit switch on.  

Some larger motorhomes, including the coach style, have a diesel / electric hot water system.

Truma, Suburban, and Atwood are some of the major players in the supply of hot water heaters for RVs.

RV Tankless Hot Water Heaters

There are various makes and models of tankless hot water systems for RV’s and they can be powered by mains electricity or gas.

For example there is the Stiebelt Electron DHC Instant Tankless Electric Water Heater or the RV500 Tankless LPG water heater.

Any gas water heaters should be installed by a licensed gas installer and comply with National Gas Standards.  Any continuous gas hot water service must be externally vented (draws air in from the outside and exhaust to the outside of your RV).

Instant Hot Water Heaters

For those of you without a RV hot water storage system one solution is to replace your sink tap/faucet with a RV Instant Hot Water appliance and connect it to mains power point in your RV.  It can be hard wired into the RV but installation should be done by a licensed electrician.  Your RV must have a 15 amp circuit. 

This ceramic device and tap provides instant hot (and cold) running water to your caravan, trailer, RV or motorhome.  The manufacturer states it runs on normal mains pressure and delivers water in the temperature range of Cold – 50 degree C.  For mains pressure and pump water you will need a no return valve on each line and the pump will need to operate at a rate of more than 4 litres per minute.

The RV Hot Water device operates on mains power but does not operate on 12V.  The manufacturer states the current draw is 11.2 amps – 13.2 amps.  The product can be run by a generator but it will require a 2.5 kW or a 3000 watt inverter.

Another instant hot water heater is a Rezi Electric Water Heater.  The Rezi hot water heater with the heating element power of 3.3 kW is recommended for caravan, travel trailers and motorhomes.  Rezi’s website states that the lifespan of the unit, provided instructions and recommendations of the manufacturer are met, is 8 years.

Storage Water Heaters for RVs

RV storage water heater tanks are designed to withstand water pressures of about 45 psi so if you are using city or town mains water you may wish to use a water pressure limiter to protect the storage tank.  Maintenance of RV storage water heater tanks should be carried out as per the manufacture’s instructions.

RV water heaters with storage tanks may be run or powered by LPG (liquefied petroleum gas) or 230/240 mains electricity whilst others can have the option to operate on either LPG or electricity.

Truma Boiler

The Truma storage water heater operates on LPG or 230/240V mains power.  Truma state their water heater storage tank is made from high quality food-proof stainless steel VA.  For maintenance they recommend using wine vinegar for de-scaling the water heater by introducing it into the appliance via the water supply.  Allow the wine vinegar to react and then thoroughly flush out the appliance with plenty of fresh water.  To sterilise the water, Truma recommend ‘Certisil-Argento’ and state other products, particularly those containing chlorine are unsuitable.  To avoid the colonization of micro-organisms, heat up the Truma Boiler to 70 degrees C at regular intervals.

Truma recommend you do not use the hot storage water as drinking water.
 

For those of you who live in colder climates where you experience frost or freezing temperatures and your RV or mobile home is not used during this time Truma state it is essential that the boiler hot water heater be emptied.

Suburban Water Heaters

Suburban storage water heaters are available in various holding capacities and combination gas/electric models are also available.  Heated water attacks metals but not porcelain so Suburban uses porcelain lined steel water tank with an anode rod to ‘absorb’ the electrolytic action. 

Suburban also have certain model water heaters available for motorhomes with a motor aid heat exchange that utilises heat from the motorhome’s engine to help heat water during operation.

Duoetto Hot Water Heaters

Duoetto manufacture a 5 litre (1 gallon) and 10 litre (2 gallon) electric water heaters.  The Duoetto 10 litre (2 gallons) mini electric water heater is ideal for an RV shower.  The tank is made from high quality food grade 304 stainless steel and its size is 430mm x 220mm x 230mm (roughly 16”x 8”x 9”).  The Duoetto features a variable thermostat 30-75 degree C on 240 V.  Power consumption of the Duoetto hot water heater is 12V -25 amps and 240V - 4.5 amps and the unit comes with automatic voltage detection for switching from 12V to 240 volt.

These units are available through AusJ Imports and Camec.

Anode Rods for RV water heaters

A sacrificial anode rod protects the hot water heater holding tank from corrosion by attracting corrosive elements in the water so they attack the rod instead of the tank.

Anode rods are used in Suburban and some Atwood storage water heater tanks and they should be checked after each big trip or about every 6 months.  Suburban recommend replacement of the anode rod when consumption or weight loss of the rod is greater than 75%. To remove the Suburban anode rod you will need an 1-1/16” socket. 

For instructions on how to replace a sacrificial anode refer here

Information obtained from a USA supplier which was posted on a forum states ‘Galvanic (sacrificial) anodes for cathodic protection falls under Australian Standards (AS) 2239 -2003.  Under the AS 2239-2003 there is 3 anode groups – zinc alloy anodes used in marine applications and as earthing anodes, aluminium alloy anodes mainly used in clean seawater and general marine use with the exception of a special chemistry for use in potable (drinking water) and magnesium alloy anodes generally used in freshwater (drinking water).

The Aluminium anode for use in drinking water is made from high purity Aluminium and alloyed to a specific chemistry, usually produced in extruded rod form in a diameter of 17 mm , fitted with threaded steel plug.

The Australian manufactured Aluminium anodes have the top of the steel plug colour coded blue for ease of identification.

This anode application is mainly used in areas of "hard "water, high in total  dissolved solids, where the TDS is in the range of 600-2500 mg/litre.

The Magnesium alloy anodes that are used for the protection of hotwater systems are produced in two specifications.

There application for drinking water is as follows.

1. M1 used in areas of high purity drinking water ie Alpine.TDS levels 0-40 mg/Litre

The Australian manufactured assy is usually 21 mm dia rod. The top of the steel plug is colour code Green for identification.

Note very few of the M1 type is sold or used for general hotwater systems

2. M2 the main anode chemistry for use in hotwater systems.

For use where the TDS levels are 40-600 mg/Litre.

The Australian manufactured assy is usually 21 mm dia (can be 26 mm dia for larger domestic and industrial systems) The top of the steel plug is colour coded Black or Orange’.

We are informed that all Suburban water heaters come from the factory with a magnesium anode rod.  It is suggested you use an aluminium rod if you come from an area with poor water quality as the aluminium rods do not degrade as fast. The use of any water softener will also degrade the magnesium anode rod quicker.

Regular flushing of the hot water tank (and even the fresh water tank) to remove any build up of ‘gunk’ should help the life of an anode rod and eliminate any bad smells.

Some people we know purchase the anode rods through an online store in the USA called rvingoutpost.com.  Anode rods are also available from RV accessory stores and eBay.

For more information do a Google search here.

 
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