A hot water system that refuses to provide hot water is among the most common issues that a caravan owner faces on the road. It’s a frustrating situation to be in and even more so - to get out of. With so many valves, connections and components, zeroing in on the problem seems near impossible. Lets attempt to simplify the troubleshooting process into 3 steps and with any luck you should be able to regain access to hot water. If not, you should seek the advice of a qualified technician.
1. Check For Gas or Electrical Supply Issues
More often than not, hot water systems stop working because of a fault in the gas or power supply. If your hot water system runs on gas, your other gas-powered appliances can give you a clue as to whether gas is reaching your system. If they seem to be malfunctioning as well, check the main regulator pressure. It should ideally be 2.8kPa. If all of this is in order and it’s just your hot water system that isn’t powering on, check for physical obstructions in the pipe carrying gas to the burner assembly. This is a common place for wasps or spiders to set up shop, and might need some cleaning. In rare cases, the burner itself is the problem. Again, it’ll mostly be a physical obstruction such as excess carbon build-up, which a jet of compressed air can remove.
Maintenance Tip: For electric hot water systems, check that the electrical connection is in order. For gas hot water systems you should be checking that the lines are free from damaged and all fittings are snug.
2. Check The Water Supply Line
The water supply to your hot water system is regulated at various points, and any of these could be the source of your problem. Start by turning off the hot water system. In most caravans, the switch (two switches in case of dual mode hot water systems) is located under the kitchen sink. Also turn off the water pump, which is controlled by another rocker switch below your kitchen sink. There should be a light here to indicate whether the pump is on or off, though you can always turn on a tap and listen to hear whether the pump is working. Make sure that it’s off, close the tap, and proceed to check the water supply for your caravan hot water system.
Head to your caravan’s utilities bay and check the position of the water heater bypass lever. This should be in the ‘normal’ position, and not the ‘bypass’ position. The latter option lets you omit the hot water system from your caravan’s plumbing, useful for when you don’t need to use it. In the ‘normal’ setting, turn on a tap to check that the flow of water is about the same in both hot and cold positions. Note that any outdoor shower faucets should be turned off while checking the water supply. Otherwise hot and cold water will mix and you’ll always get lukewarm water out of your taps.
Maintenance Tip: Keeping your water tank/ water supply clean and free of debris is a key factor to keeping your hot water system working when you need it most. Flushing your water lines and your hot water tanks regularly will prevent build-up of residue which can cause problems later on down the track.
3. Check The Thermostat and Heating Element
If the above steps have failed to bring out a culprit, chances are that the problem is closer to home. If you’ve checked and confirmed that the fuse is all right, and your hot water system still won’t give you any hot water, the most probable cause is a broken thermostat. If you have a dual mode (gas and electric) hot water system, and it works on gas but not in the electric mode, the heating element could be broken. These are relatively small problems, and only need a part replaced. Replacement thermostats and heating elements are easily available and can make your hot water system good as new.
Hot Water in the Kitchen but Not in the Bathroom?
This is a common and frustrating issue in caravans—scalding hot water at the kitchen sink, but cold showers in the bathroom. If you're experiencing this, the most likely culprit is a faulty tempering valve.
In caravans, all bathroom hot water flows through a tempering valve, which reduces the water temperature to a safe range between 30°C and 50°C. These valves are typically located under the caravan or near the hot water system. They usually appear as a brass cross with a coloured dial. You can purchase a replacement tempering valve here and either replace it yourself or have it ready for your plumber to install.
If none of the above steps succeed in giving you a solution to the problem, get in touch with a professional right away.
Maintenance Tips: Most caravan hot water systems will have a sacrificial anode installed. Water inside the systems tanks can become corrosive. This anode keeps the water cleaner and extends the tanks life. These need to be inspected regularly and replaced periodically.
If you think it's time for an upgrade, check out our extensive range of caravan hot water systems here.
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DISCLAIMER* Please note, this advice is general in nature and we strongly recommend consulting the product manual and where relevant, a professional installer.
Comments (73)
Gas hot water service
Having a issue with water heater on gas When you start it up on gas the system ignites but then cuts out and goes back to the start modeBy: Bryan Reeve on 04 April 2025
www.caravanrvcamping.com.au Response
Hi Bryan, there could be multiple issues at play here, as it is a gas appliance we do recommend visiting your local certified gas fitter to perform all inspections for fault finding.
No Hot Water at the tap.
I have Gas, checked, heater is on, I have also tried hot water using 240v system. I felt heat at mixer valve but I don't have heat at the tapBy: GARY on 27 March 2025
www.caravanrvcamping.com.au Response
Hi Gary, it seems like the tempering valve might be faulty or blocked. If you swap this out, it should solve your issues.
2017 jayco journey caravan
water wont fill water heater at a loss to why cold water works fineBy: Lorelle joy Rea on 17 March 2025
www.caravanrvcamping.com.au Response
Hi Lorelle, that must be so frustrating. The most common issue with hot water systems is the build of sediment or calcium from the harsh Australian water. It could be blocking the inlet into the hot water systems tank, preventing it from filling. It is important to regularly check your sacrificial anode in your system, if this has broken down then it will allow the build up to move somewhere else and cause problems. Failing this I would get someone to check the pressure relief valve, if this is malfunctioning it could cause issues.
Hot water system
Hot water system in 2023 jayco gas / electric while on gas the system works with the outer door open when you close the door the flame dies away and goes out I don’t know if this is a oxygen problem or something else. Any help would be appreciatedBy: Steven Leonard on 13 March 2025
www.caravanrvcamping.com.au Response
Hi Steven, there could a be few factors at play here. If there is a build up of dust or debris in or near the exhaust or intake vents, once the door is shut it drastically reduces the ventilation and the hot water system protection kits in and cuts the flame and gas. It could be a fault pilot light or a thermocouple as well. I would be contacting your nearest caravan repair who deals with gas and them to fully inspect and service the unit.
