How your tank detects spare solar power
How a small sensor tells your system when spare solar electricity is available.
If your home has compatible solar panels, your Mixergy tank can use some of the electricity that your home is not using. A small sensor helps the system detect when this spare solar electricity is available.
The sensor is called a CT clamp. It measures electricity flowing through a cable. The solar controls use that reading to detect electricity that would otherwise leave your home and go to the grid.
A solar diverter uses this information to send spare electricity to the tank’s electric heater. Some integrated heat-pump systems use the reading to start the heat pump instead. Your installer can tell you which arrangement you have.
The CT clamp is fitted near mains electrical equipment. Do not open covers, move the clamp or touch the cable around it. Ask a competent installer to check it.
What does a CT clamp do?
A CT clamp is a small sensor clipped around an electrical cable near your electricity supply. It measures the amount and direction of electricity flowing through the cable without touching the metal wire inside.
The measurement tells the solar controls whether your home is taking electricity from the grid or has spare solar electricity available.
What happens when the panels generate electricity?
Your solar panels first supply appliances that are running in your home. If the panels generate more than the home is using, the extra electricity would normally flow out to the grid.
The CT clamp detects this change. A compatible solar diverter can then send some of the spare electricity to the tank’s immersion heater, which is the electric heating element inside the tank.
Any electricity not used by the home or tank can still be exported to the grid.
Why must the clamp be fitted in the right place and direction?
The clamp measures which way electricity is flowing. If it is fitted around the wrong cable or faces the wrong direction, the system can misread electricity coming into the home as spare electricity going out.
The correct cable and direction depend on the equipment fitted. An installer must check this because the clamp is normally close to mains electrical equipment.
How can I check whether solar is heating the tank?
If your setup reports solar information and the tank is online, open the Mixergy app and select your tank. Open Graphs from the tank screen or main menu, then choose PV Power. PV refers to solar panels that generate electricity.
For a useful check:
- Choose a bright part of the day when the panels are generating.
- Read the hot-water level in the app. Heating can stop when the tank reaches its solar amount or temperature limit.
- If your setup has Mixergy solar controls, open the top-right menu, choose Tank Settings and look for PV Diverter Settings or PV Diverter Schedule. Read the Use spare PV to heat tank setting. See Solar settings explained before changing it.
- Avoid running high-power appliances for a short time, if convenient.
- Look for a pattern over several suitable days.
Cloud cover, household electricity use and the minimum power required by the equipment all affect whether solar is used at a particular moment.
What should I do if the app shows no solar power?
- Read your solar system’s app or display to see whether the panels are generating electricity.
- Read the hot-water level in the Mixergy app. If the tank has reached its solar amount or temperature limit, it has no further heating request.
- Use the Tank Settings route above to read the solar setting, if it is available. If it is missing, ask your installer which controls manage your solar heating.
- If another company made the diverter, read its own app or display for the amount of power being sent to the tank. Missing Mixergy data does not by itself prove the clamp is faulty.
- Try again during a longer period of strong daylight.
If the reading still remains at zero in suitable conditions, contact the solar installer, landlord or housing provider. Tell them when you checked, what the weather was like and what each app or display showed.
Can I still use the tank if the solar reading is unavailable?
Yes. The tank can still use its other configured heat source. You can also check and boost hot water using the gauge.
Related guides
Use solar PV with your Mixergy tank
Is solar PV working with your tank?
[IMAGE – SIMPLE ENERGY FLOW DIAGRAM]
Use: Solar panels to home, CT clamp at incoming supply, spare electricity to Mixergy tank and remaining export to grid.
Caption: The CT clamp helps the system detect when spare solar electricity is available.
Alt text: Diagram showing solar electricity used by the home first, with spare power available to the Mixergy tank.
Common questions
Does the CT clamp control where the electricity goes?
No. It measures electricity flow. The solar diverter uses that information to decide whether power can be sent to the tank.
Will the tank use all my spare solar electricity?
Not necessarily. It depends on the amount available, the hot-water level, solar settings and the equipment fitted.
Why does the reading change so quickly?
Solar generation and household electricity use both change throughout the day. Clouds, kettles, ovens and other appliances can alter the spare amount within seconds.
Can I fit, turn around or move the clamp myself?
No. It must be placed on the correct cable in the correct direction and is normally close to mains electricity. Ask a competent installer.
Does a zero reading mean the clamp is faulty?
No. There may be no spare electricity, the tank may already be hot or the installation may not report solar information to Mixergy. Check the conditions before arranging an installer visit.