Common Issues With Solar Hot Water Systems


Solar hot water installation is a great way to make your home more energy efficient and save money on heating your water. 

However, when something goes wrong with our hot water system, it can be very frustrating. 

Understanding the common problems can help you figure out what is wrong before calling in professional help. It’s important to fix issues as soon as possible so that they don’t compound and become more costly to fix later on.

Check out the common issues with solar hot water systems and ways to fix them below. 

No hot water / Water isn’t hot enough

There could be a number of reasons why you aren’t getting enough or any hot water from your system. Work through the steps below to problem solve the issue:


  1. Check the solar panels. Make sure they are clear from dirt and debris and that there are no branches or other obstacles blocking the sunlight around the panels. Also check that the surface is not damaged.
  2. Do you have a back up heater? On overcast days your solar panels may not generate much electricity to heat your water properly. If you do not have a backup heater or connection to the grid, this may be the cause of not enough hot water.
  3. Check the thermostat. If it is set too low, your water will not get very hot. If there is a problem with the thermostat, this may also cause your water to not be heated properly.
  4. Check the wiring for any faults. Issues with electrical connections, such as the sensor, may cause problems with heating the water.
  5. Insulate the hot water tank. Without proper insulation, your hot water tank may be losing a lot of heat and struggling to stay warm.


Leaks may be caused by a number of things such as a broken pipe, damage to the pressure relief valve or loose pipe fittings.

If you notice that your system is leaking, try the following troubleshooting steps:

  1. Check the pipe fittings. Tighten any loose fittings and replace any broken ones.
  2. Try replacing the pressure relief valve and the seal.
  3. Check the solar panels for any damage and replace or repair if need be.
  4. Lower the thermostat to reduce the amount of pressure on the system.

Strange noises

If you turn your hot water pump on and notice unusual noises, it could indicate a problem with the system.

Noises can be a symptom of a few different problems such as sediment build up in the system, obstructions to the impeller, broken components or trapped air.

Follow the troubleshooting steps below to find out what the issue is:

  1. Clean the impellers of any mineral build up.
  2. Lubricate the bearings.
  3. Loosen the vent screw to remove air from the system. Ensure that nothing is blocking the air vent.
  4. Consider replacing the pump if problems persist.

Loose connections

Loose connections or issues with the wiring can cause problems with your solar hot water heater.

Check the wire connections for any faults. Damaged parts will need to be cut out and reconnected as appropriate. To avoid any safety hazards, you should call a professional to help repair loose connections.

Mineral build up

In places like Perth and Mandurah, the water is described as hard. This means there is a high amount of dissolved minerals in the water. These minerals may build up in the hot water system, creating mineral deposits that can ultimately clog the system. 

Hot water systems should be regularly checked for mineral deposits and cleaned accordingly. A medium grade sandpaper can be used to clean scaling off the heat exchanger surfaces. 

You can also add a water softener or mild acidic solution such as vinegar to your hot water supply to help prevent mineral build up in the future. This can be done every 3 to 5 years or as recommended by a professional.

Solar panel problems

Issues with your solar panels can lead to hot water system failure. There are a number of potential solar panel problems including:

  • Damaged solar panels and broken glass. In this case, the glass or the entire panel will need to be replaced.
  • Dirt build up can reduce solar panel efficiency. Make sure you regularly clean your solar panels, especially if you live in a dusty or dry location.
  • Shading can reduce the effectiveness of solar panels. Clear away any branches or foliage that casts shade on the panel. Consider if your solar panel is placed in the optimal position for maximum sunlight throughout the day.
  • If you have plastic glazing that is turning yellow, it is a sign that it needs replacing.
  • Condensation formed on the glass may collect at the bottom of the panels and reduce efficiency. Adding a weep hole will help drain the water away.
  • If water gets into the panel it can cause corrosion. Ensure your panels are watertight to prevent corrosion.

Prevent solar hot water system problems with regular maintenance

The best way to prevent problems with your solar hot water system is to have it regularly serviced. Hiring a professional to perform maintenance on your hot water system will ensure it stays in good working condition, and a professional may be able to catch and prevent issues before they become too large.

Don’t wait until the problem gets worse – call in a professional today to get your system back in good working condition as soon as possible.

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