Troubleshooting and Repairing a Solar Water Heating System

Does your solar water heating system not work on overcast or rainy days? Then you may have a problem with the emergency electrical heating system.

In this comprehensive guide, we will show you how to troubleshoot and repair a solar water heating system's emergency electrical system. We will walk you through the steps necessary to diagnose the issue and carry out the necessary repairs.

Please remember that, when working with any electrical appliances, safety should always be your top priority, and we also suggest you watch our video.

Additionally, you can visit our web store to buy genuine spare parts: https://shop.how-to-repair.com/

Tools and Materials Needed:

• Multimeter (AC voltage and amperage settings)
• Screwdriver
• New thermostat and heating element (if needed)
• Replacement anode

Identifying the Problem & Checking the Emergency Electrical System

The issue presented in this case is an underperforming solar water heating system, consisting of two panels and a 300-liter tank. Despite the system's capacity to provide hot water for the house most of the year, during extended periods of overcast or rainy weather, the system fails to generate sufficient heat. To supplement the heat supply during such periods, the system is equipped with an emergency electrical system. However, this system is currently not functioning.

The emergency electrical system is located behind a panel on the water heating unit. To access it, remove the screws securing the panel and take it off. You will find an earthing wire, a neutral wire, and a live wire.

Now, we will explain the instructions step by step:

1. Measuring Power Draw

The first step in diagnosing the issue is to ensure that electricity is reaching the heater unit. Set a multimeter to AC voltage and test across the two wires going to the thermostat. A reading of 240 volts indicates that electricity is reaching the unit.

Next, check the thermostat adjustment for temperature control. If you hear a clicking sound when adjusting the thermostat, this means the points are operating correctly. Yet, if no heat is generated, it could indicate a faulty thermostat or a faulty heater.

Using a multimeter set to AC amperage, you can measure the power drawn by the system. Attach the meter to the live wire, and when the thermostat activates, you should see a power draw ranging from 1500 watts to 3000 watts, depending on the size of the installed heating element. If no power is being drawn, it indicates a problem with the thermostat or the heater.

2. Checking the Heating Element

To check the heating element, you first need to disconnect the power from the house entirely and drain the tank. Once power is disconnected, tape up the ends of the wires for safety and disconnect the electrical unit.

The thermostat is usually mounted on top of the heating element and connected via two spade connectors. Remove these to expose the element.

3. Testing the Heating Element

Set your multimeter to ohms and perform a continuity test on the element by connecting the meter across the two element terminals. If the element is functioning correctly, you should get an ohms reading. In this case, the element, which is marked 2000 Watts at 220 volts, gives a reading of 24.7 - 24.8 ohms.

By following these steps, you can diagnose and repair issues with the emergency electrical system in your solar water heating system. Remember, if you're unsure about any of these processes or uncomfortable performing them, you can either watch our video carefully or seek help from a professional.

4. Draining and Inspecting the Tank

Before proceeding with the repair, you should drain the tank and disconnect the unit from the power supply. After disconnecting the power, tape up the ends of the wires for safety.

Once the tank is drained, inspect the heating element and the anode for signs of wear and tear. The anode is designed to prevent electrolysis in the tank and should be replaced every three to five years.

5. Checking the Thermostat

The thermostat is usually mounted on top of the heating element and connected via two spade connectors. You will need to remove these to expose the element.

To check if the thermostat is working, set your multimeter to ohms and perform a continuity test on the element. If the element is functioning correctly, you should get an ohms reading. If there is no reading, the thermostat may be faulty.

6. Replacing the Thermostat and Heating Element

If the thermostat is faulty, it's advisable to replace the entire unit, including the heating element and anode. The reasons for replacing all three parts are twofold.

Firstly, the anode needs replacing every three to five years, and secondly, cleaning the inside of the tank will reveal a lot of calcium and other deposits, which can affect the performance of the heating element and the tank itself.

7. Preparing for Installation the New Parts

Before installing the new parts, turn off the cold water supply going to the tank and drain the system. As you undo the bolts securing the heating element, some water might escape due to the vacuum created in the tank. You can break this vacuum by loosening the small nuts on the plate.

Once the tank is drained, you can install the new heating element, anode, and thermostat. Please ensure to attach the anode and heating element so they do not interfere with each other. Once the new parts are securely attached, you can refill the tank and restore the power supply.

8. Final Checks

After the installation, set your multimeter to AC voltage and perform a final check to ensure the electrical system is working correctly. Test across the feed into the thermostat and the two wires that come out from the thermostat to the heating element. If the readings are as expected, this indicates a successful repair.

By following this guide, you can diagnose and repair issues with the emergency electrical system in your solar water heating system.

Preventative maintenance is crucial for the longevity of your solar water heating system. Regular checks and replacements of the anode and the heating system every three to five years can prevent issues like this from occurring. Additionally, every five years, we recommend that you replace the glycol that runs through the solar water system.

Remember, if you're unsure about any of these steps or uncomfortable performing them, you can watch our video to ease your worries.