One essential aspect of hot water system maintenance is regularly draining and flushing the tank. This process helps remove sediment build-up, prevent rust, and improve overall efficiency. In this guide, we’ll explore how to drain different types of water heating units, how long it takes, and how often you should perform this maintenance task.
Why Drain Your Hot Water Heating System?
Before we dive into the specifics, let’s understand why draining hot water systems is important:
- Mineral deposits and sediment can accumulate at the bottom of the tank over time, reducing efficiency and potentially causing damage.
- Flushing the system helps remove rusty water and reduces the risk of corrosion.
- Regular draining ensures cleaner, fresher hot water for your home.
- Proper maintenance can significantly increase the lifespan of your hot water unit.
Note: Switch off your hot water at least 6 hours before emptying it. We don’t recommend emptying your hot water unit until the water in the tank has cooled down.
How to Drain an Electric Hot Water System
Follow these steps to flush your electric hot water system:
- Turn off the power supply: Locate the circuit breaker for your hot water and switch it off. Allow a couple of hours for your hot water to cool.
- Turn off the cold water supply: Find the cold water inlet valve and close it to stop the water from flowing into the tank.
- Connect a hose: Attach a garden hose to the drain at the bottom of the tank. Ensure the other end of the hose leads to a suitable drainage area.
- Open a hot water tap: This allows air to enter the system, facilitating drainage.
- Open the ball valve: Carefully open the drain valve to begin emptying the tank.
- Flush the system: Once the tank is empty, briefly open the cold water supply line to run cold water through the tank and flush out any remaining sediment.
- Close valves and refill: Turn off the hot tap you turned on in step 4. To refill the tank with tap water, close the drain valve, disconnect the hose, and open the cold water intake.
- Restore power: Once the tank is full, turn the power back on at the circuit breaker.
How to Drain a Gas Hot Water System
The process for emptying a gas hot water service is similar to an electric system, with a few key differences:
- Turn off the gas supply: Locate the gas valve and turn it to the “OFF” position. Allow time for the water to cool.
- Follow steps 2-6 from the electric system instructions above.
- Flush the system: Open the cold water inlet briefly to flush out sediment.
- Close valves and refill: Close the drain valve, remove the hose, and open the cold water inlet to refill the tank.
- Relight the pilot: Follow the manufacturer’s instructions to relight the pilot light and restore gas flow.
How to Drain a Solar Hot Water Heater
Draining a solar water heater tank requires extra care due to its unique configuration:
- Turn off the booster element: If your system has an electric booster, switch it off at the circuit breaker.
- Cover solar collectors: Place a cover over the solar collectors to prevent overheating during the draining process.
- Follow steps 2-6 from the electric system instructions.
- Drain solar collectors: Open the solar collector drain valves to empty the panels.
- Flush the system: Briefly open the cold water inflow valve to flush out sediment.
- Close valves and refill: Close all drain valves, remove the drain hose, and open the cold water valve to refill the system.
- Remove collector covers and restore power: Uncover the solar collectors and turn the booster element back on if applicable.
How to Drain a Heat Pump Hot Water System
Heat pump systems are becoming increasingly popular due to their energy efficiency. Here’s how to drain one:
- Turn off the power: Switch off the heat pump at the circuit breaker. Allow time for the water to cool.
- Isolate the unit: Close the cold water inlet valve to stop water flow into the tank.
- Connect a hose: Attach a garden hose to the drain valve at the bottom of the tank, ensuring the other end leads to a suitable drainage area.
- Release pressure: Open a hot water tap in your home to allow air into the system.
- Drain the tank: Open the drain valve and allow the tank to empty completely.
- Flush the system: Once empty, briefly open the cold water inlet to flush out any remaining sediment.
- Clean the filter: Many heat pump systems have a filter that should be cleaned during this process. Consult your user manual for its location and cleaning instructions.
- Close and refill: Close the drain valve, remove the hose, and open the cold water inlet to refill the tank with fresh water.
- Restart the system: Once full, close all taps and restore power to the unit.
Remember, heat pump systems often have specific maintenance requirements. If you’re unsure about any step in the process, consult your user manual or give us a call at Drain Defenders. We regularly work with heat pump systems and are happy to assist.
How Long Does It Take to Flush a Hot Water System?
On average, it takes 20-60 minutes to fully drain a hot water tank depending on the size. Remember to allow time for the tank to cool down before starting the draining process, which can add several hours to the total time.
Why Cool The Water Before Draining the Tank?
Allowing time for a hot water tank to cool before draining it is an important safety precaution. Here’s why:
- Safety: The primary reason is to prevent burns or scalding. Water in a hot water tank can reach temperatures of 60°C (140°F) or higher, which can cause burns instantly.
- Pressure reduction: As water cools, it contracts, reducing pressure inside the tank, making the process safer and easier to control.
- Prevent damage: Draining very hot water can potentially damage or warp PVC pipes or other plumbing components not designed to handle higher temperatures.
- Energy efficiency: Allowing the water to cool naturally saves the energy that was used to heat it, rather than immediately flushing hot water down the drain.
- Sediment settling: Cooling time allows sediment to settle at the bottom of the tank.
- Reduced steam: Cooler water produces less steam, improving visibility and making the process safer.
- Tank protection: Sudden temperature changes can stress the tank material. Gradual cooling helps preserve the tank’s integrity.
While it’s possible to purge a hot water tank without waiting for it to cool, it’s recommended to wait at least a few hours after the last use of hot water or turning off the heating element.
How Often Do I Need to Drain the Tank?
For optimal performance and longevity, it’s recommended to empty your hot water system annually. However, if you notice any of the following signs, you may need to drain your system more frequently:
- Rusty or discoloured water coming from hot taps
- Reduced water pressure or flow from hot taps
- Unusual noises coming from the tank
- Visible leaks, rust or corrosion on the tank exterior
If you live in an area with hard water, you may need to drain and flush your system more often, as mineral deposits can accumulate faster.
Additional Tips for Specific Hot Water Brands
While the general process for removing water is similar across brands, there may be slight variations. Here are some brand-specific considerations:
Dux
Dux are known for their reliability and efficiency. When emptying a Dux unit:
- Locate the temperature pressure relief valve (TPR) and operate it manually to ensure it’s functioning correctly before and after draining.
- Pay special attention to the anode rod, which may need replacement every 5 years or so to prevent corrosion.
Rheem
Rheem is a popular brand in Queensland. When emptying a Rheem:
- For gas systems, follow the specific instructions in your user manual for relighting the pilot light after draining.
- Some Rheem electric models have dual heating elements. Ensure both elements are switched off before releasing the water.
Vulcan:
Vulcan hot water units are designed for durability. When removing water from a Vulcan system:
- Check the pressure limiting valve (if installed) during the process to ensure it’s working correctly.
- For Vulcan heat pump systems, consult the user manual for specific instructions on flushing the heat exchanger coils.
Associated Reading:
FAQ’s
Do I Need to flush an instantaneous hot water unit?
Why is my hot water rusty after emptying and refilling my tank?
What’s the difference between draining and flushing?
Final Tips for Emptying Your Hot Water System
1. Safety first: Always exercise caution when dealing with hot water and electrical or gas components. If you’re unsure, consult our licensed plumbers in Logan.
2. Timing matters: Consider draining your system during off-peak hours to minimise disruption to your household’s hot water supply.
3. Check for leaks: After refilling the tank, inspect all connections and valves for any signs of leakage.
4. Consider professional service: While draining hot water stored can be a DIY task, having our professional plumbers perform maintenance of your hot water unit can help identify potential issues and ensure thorough servicing.
By following these guidelines and regularly maintaining your hot water system, you’ll enjoy reliable hot water, improved efficiency, and a longer-lasting unit. Remember, if you encounter any difficulties or are unsure about any step in the process, don’t hesitate to give us a call.