By Patrick Gordon of Calafrica (technical@calafrica.co.za)
What are some of the uses for a diverter valve?
A diverter valve is a piece of equipment that changes the direction of water flow without any human intervention. The only setting that is required, is to set the predetermined temperature that you would like the switching to take place at.

Image supplied by Patrick Gordon
The most popular use for a diverter valve is in a heat pump installation. If the water circulating in the primary loop has not yet reached the optimal temperature, the valve keeps it in the loop until it has reached the set temperature. Once the set temperature is achieved, the valve routes the water to the secondary loop that replaces some of the cold water in the hot water cylinder with hot water. As soon as the temperature of the circulating water in the loop again drops below a certain level, the valve will again route the water to the primary loop. By using this type of installation, hot water is dumped into the top of the hot water cylinder and cold water is removed from the cylinder. This way of doing the installation prevents the disturbance of the stratification of the contents of the cylinder.
Another innovative way of using the valve is to include a gas heater in a solar installation. During some scenarios the water in the storage tank may not be hot enough. This could typically be when the panels have not been able to absorb enough energy due to consecutive cloudy days. Instead of connecting electricity to the heating cycle (loadshedding is a reality), homeowners are now opting to add a gas heating system.
But how can you route this automatically?
By using the diverter valve, the heated water from the solar system will automatically be flowing to the normal plumbing installation. If, however, the water has not been sufficiently heated, the flow will now be diverted to the gas heater to bring it to the desired temperature.
How does it achieve these operations?
- The water from the storage tank enters the bottom port
- and flows over the thermal probe
- The probe will expand and contract as it senses the temperature of the water that is in contact with it. If the temperature is higher than the valves setting, the water will be directed to the port to the left
- If the water temperature is lower than the set temperature, the water will be diverted to the port on the right

Image supplied by Patrick Gordon
I am sure if the installer applies their mind to the valve’s capabilities, many other types of installations could benefit using this type of valve.
For any further information regarding this topic please feel free to contact:
Patrick Gordon at 083 303 1437