PV diverter not working
Reset first, then check the clamp, the output and the board.
A reset clears a tripped diverter thermostat and resolves many cases without a replacement part. After that, check the clamp, then the output, then the board.
SAFETY
Only carry out electrical or unvented hot water checks if you are competent to do so. Isolate the supply and prove it dead before you remove covers or touch wiring, and never ask a homeowner or resident to access live components.
Follow these checks in order
1. Reset the diverter
Power off at the spur so no lights are lit, press the red button or buttons on the underside of the diverter firmly (with a screwdriver or pin), then power back on. Is it diverting again?
- If yes, the diverter thermostat had tripped. Note the reset time so support can check it on the servers.
- If not, go to step 2.
2. Check for a clamp reading
Is a CT clamp reading visible in the app?
- If not, the diverter can't see export, so it won't divert. See Check the CT clamp and interface.
- If yes, go to step 3.
3. Check the diverter output
With clear export showing, does the diverter send power to the immersion?
- If yes, the diverter is working. If the customer still reports low solar capture, check the headroom and the diverter time windows. See Solar PV not heating the cylinder and App settings causing unexpected heating.
- If not, go to step 4.
4. Test the immersion and the diverter
The immersion element tests OK (continuity L to N, no short to earth; see Test an immersion heater), but there's no output from the diverter when it's commanded?
- If yes, it's likely a board-level fault, such as a stuck relay or a failed thermal fuse. Contact Mixergy support with the MX number to arrange a replacement diverter.
- If not, go to step 5.
5. Check for noise, clicking or dropouts
Is there fan noise, repeated clicking or intermittent dropout?
- If yes, contact Mixergy support with the MX number and dates. A software fix exists for some clicking cases, while fan faults need a replacement diverter.
- If not, suspect the wiring, for example the diverter bypassed internally, wired to the PV live, or an undersized supply. An electrician or engineer needs to check the installation.