Replacing a hot water system tank

By: Philip Lord


All you need to know about replacing a hot water system tank.

Caravan hot water systems (HWS) are usually very reliable component but, like anything, they can eventually cause problems. The two most common issues are either with a heater anode failure or a leak developing from the tank.

This HWS had sprung a leak so it was time to pull it out and check out what was going on.

Hot -water -service -in -a -caravan

Caravan HWS run on either 240V mains power or gas. This is where you will strike problems as a DIYer – you need to have a certified gas fitter approve your work (or do the work) for reconnecting the copper gas line, and if the 240V side of the system is hardwired into the van (some just plug into a wall socket) then you’ll need a licensed electrician to assist.

But don’t even attempt this job if you haven’t got this vital safety element covered off – gas fittings and 240V wiring require qualified tradesmen to work on them for a reason. Get it wrong and you’ll risk injuring yourself or someone else – or worse.

However, you can save some costs by doing the bulk of the work yourself, or see what’s involved when a repair shop does the job for you.

Replacing a tank can take either not much more than an hour or many, many hours – it all depends on how much the HWS was built into the van. Caravans are usually built from the outside in – the floor and cabinetry is built on top of the chassis then the external walls are installed. It can mean that items such as a HWS can be hard to access.

1. In this case, the HWS was built into a lower cabinet in the corner of the bathroom. The toilet was removed, giving much better access. If this was not possible or if there were other cabinets impeding access, cutting out the cabinet shelf would have been the only option.

2. The toilet cassette was removed to gain access to the screws holding the toilet down and these screws were removed. The toilet could then be removed from the van.

Toilet -casette -and -the -toilet -are -taken -out -in -a -caravan

3. Then outside the van, the HWS air inlet/exhaust (for gas operation) cover andsecuring plate were removed.

Exhaust -air -inlet -cover -and -how -water -system -are -removed

4. Back in the van, the screws securing the HWS to the floor were removed.

The -hot -water -service -floor -tang -screws -are -removed

5. The water inlet/outlet pipe connections disconnected.

Water -connections -are -disconnected -in -a -caravan

6. You need to use a sliding collar to ensure a positive connection so they can be a bit tricky to disconnect. With these removed, the HWS was free to slide out from the enclosure.

The -water -tank -is -removed -from -its -compartment

7. Now that it can be accessed, the gas line is disconnected.

The -gas -line -is -disconnected -in -a -caravan

8. That gave access to the 12V electrical connections (12V is for gas ignition only) so they could be released and allow the gas inlet pipe connection to be unscrewed.

Power -connections -are -disconnected -from -the -water -tank -in -a -caravan

9. In this case, 240V was disconnected by simply pulling the plug out of the 240V mains socket in the adjacent cabinet wall.

The -240v -power -cord -is -removed -from -a -caravan -water -system

10. The HWS could then be removed from the van to be further dismantled on the work bench.

Caravan -hot -water -service -outer -cover -disassembled

11. The printed circuit board enclosure was dismantled and removed to allow the cardboard enclosure to be taken off.

Printed -Control -Board -removed -from -the -outer -cover -of -the -hot -water -system -in -a -caravan

12. The exhaust outlet/air inlet assembly was removed.

Inlet -exhaust -assembly -removed -from -the -water -system -in -a -caravan

13. Heating element removed. You can see on image above, the water stains left from the leaking tank.

Heating -element -removed -from -a -caravan -water -system

14. Next the tank’s retaining collar was removed, followed by the tank itself.

Retaining -collar -and -water -tank -are -removed -from -the -caravan -water -system

15. Installation is the reverse procedure. But certified fitters must be involved with the gas connection and, in cases where 240V is hard-wired, the electrical connection.

The -new -water -tank -is -dropped -into -the -body -of -the -unit

With thanks to Barnes Caravans, 121 Hume Highway, Lansvale NSW 2166, (02) 9728 6366, for their assistance with this story.