Mixergy with third-party solar diverters FAQ
Answers to common questions about using a Mixergy tank with another company's diverter.
A solar diverter detects electricity your panels generate that your home is not using, then sends it to heat water. A third-party diverter is made by another company. A compatible Mixergy installation uses a PV Switch to connect it to the tank.
The third-party diverter controls the spare electricity sent to the tank’s immersion heater. The Mixergy app may therefore show less information or provide fewer solar controls than it does with an integrated Mixergy solar setup.
Who should check a problem?
Contact the original solar installer or diverter provider if the diverter shows power being sent but the hot water level does not rise. Record the readings and when this happened. If you rent, contact your landlord or housing provider.
A CT clamp is the sensor around a cable that measures electricity flow. Leave it in place. Do not open the PV Switch or electrical covers, and leave wiring and thermostats to a competent installer.
[IMAGE – THIRD-PARTY DIVERTER SETUP]
Use: Solar panels, third-party diverter, Mixergy PV Switch and Mixergy tank.
Caption: The external diverter controls spare solar power; the PV Switch connects it to the tank’s immersion heater.
Alt text: Diagram showing solar panels connected to a third-party diverter, Mixergy PV Switch and tank.
Common questions
Can my tank use a third-party diverter, and what is the PV Switch?
Third-party means equipment made by another company. Compatible Mixergy X installations use a Mixergy PV Switch to connect that diverter to the tank. Your installer must confirm the exact equipment and wiring are suitable. The switch can be added to a compatible existing installation.
Examples include myenergi Eddi, Solar iBoost+ and Solic 200. Having one of these does not replace the need for the correct Mixergy connection.
The PV Switch lets the immersion heater, the electric heating element inside the tank, receive varying amounts of power from the diverter. This can heat usable water at the top first. You do not need to operate the switch yourself.
Who controls solar heating, and can I set a limit in Mixergy?
The external diverter decides when and how much spare electricity to send. Your tank keeps its usual Mixergy controls, including hot-water level readings and Boost. Solar diversion can run outside a normal heating schedule.
Mixergy cannot normally stop third-party solar diversion at a chosen hot water percentage. The digital solar temperature target in the Mixergy app also does not control the externally supplied power. The immersion heater’s thermostat limits its temperature during diversion.
Ask your installer to confirm a suitable thermostat setting and whether your diverter offers its own heating limit. Do not open covers or adjust thermostats yourself. See Solar settings explained for how supported Mixergy solar controls differ.
Why does Mixergy show no solar energy while the tank heats?
Power supplied through a third-party diverter is not recorded in Mixergy in the same way as power controlled by the tank. An empty solar graph therefore does not prove that solar heating has failed.
Read the diverter’s own display or app to see whether it is sending power. In Mixergy, select your tank and compare the hot-water level before and after that period. Other active heat sources can also make the level rise. See Is solar PV working with your tank? for a fuller check.
How can I leave room for solar heating later in the day?
If your installed system supports partial heating, a smaller morning amount can meet your early needs while leaving more cold water available to heat with spare solar later. This means changing how much water is heated, not leaving the tank physically empty.
Follow your installer’s advice, especially if you also use a heat pump. Make small changes to a manual schedule and compare several normal days. Keep enough hot water for your needs; do not base the schedule on an unusually sunny day. See Set schedules and smart control before making a change.
Why is the diverter sending power but the water is not heating?
The tank can already be hot enough for its thermostat to stop heating. Another possibility is a safety cut-out or a connection problem. The display alone cannot tell you which applies.
Record what the diverter shows and whether the hot-water level changes. Ask the solar installer or diverter provider to investigate if the problem continues; do not reset hidden safety controls or change wiring yourself.