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MDC0014-03 PV Switch Installation

Installation and commissioning instructions for the Mixergy PV Switch

Download the installation guide (PDF, 496kb)


About this module

The Mixergy PV switch is an intermediary relay device which allows external 3rd party PV diverters to be integrated with the Mixergy cylinder and share use of the primary immersion.

Under idle conditions, control of the immersion is given to the PV diverter. Whenever the Mixergy controller calls for heat through the immersion via boost or a scheduled heating event, control of the immersion is switched away from the PV diverter and given to the Mixergy controller. 

Technical data

Supported (input) diverter(s) 1
Supported (output) immersion(s) 1
Supported immersion rating 230-240 V~ 2.7-3.0 kW
Supported immersion specification EN 60335-2-73 
Max. idle consumption (12V) 250 mW
Max. active consumption (12V) 1500 mW

Included items

  • MAS0086-01 PV ready switch box complete
  • MEL0049 2m pump cable extension
  • 2x MME0077 Screw No 8 x 13mm Self Drilling
  • 2x MME0152 Plastic spacer
  • Installation guide

Installation: general guidelines


Ensure that all mains cabling used have a minimum CSA of 1.5 mm2 with a minimum temperature rating of 90C (H05V2V2-F).

Avoid fitting the PV switch or making electrical junctions directly underneath water pipework.

The PV switch can be fixed to the outer wrapper of the cylinder using the two self-drilling screws or to an adjacent wall using the provided plastic spacers. In the case of a wall mount, the immersion cable will need to be extended. Ensure that the junction used to perform this extension has a minimum IP41 rating and is appropriately rated to handle 240V~ 13A continuous.

Installation: mechanical

1. Remove the front cover of the PV switch.

2. Mount the PV switch either to the side wall of the cylinder (using the included self-drilling screws) or to a nearby wall (using the included plastic spacers).

3. Remove the cover/cap on the primary immersion heater. Disconnect the Mixergy controller’s immersion supply cable from the immersion’s terminals.






Installation: electrical

4. Wire the Mixergy controller’s immersion supply cable into the terminals MXL(L), MXN(N), GND(E) on the PV switch. This cable can be extended using minimum 1.5mm2 CSA 3-core
H05V2V2-F flex if required.

5. Wire the external diverter’s immersion supply cable into the terminals PVL(L), PVN(N), GND(E) on the PV switch.

6. Wire an appropriate length of minimum 1.5mm2 CSA 3-core H05V2V2-F flex from the PV switch terminals IML(L), IMN(N), GND(E) to the cylinder’s primary immersion heater terminals L, N, E.


7. Remove the Mixergy cylinder controller's top cover by unscrewing the screws shown below and pulling the cover away.

8. Unplug the pump from the cylinder controller.

9. Plug the pump cable into either pump port on the PV switch.

10. Plug the included pump extension lead from the second pump port on the PV switch to the pump port on the cylinder controller.

11. Adjust the immersion thermostat to approx. 65 C. For thermostats without discrete temperature steps, move the dial to the 3/4 of max position. Note that this may need to be adjusted after the system has been tested.

12. Replace immersion cover, PV switch cover and cylinder controller

MDC0014-03-PV-Switch-Installation-Guide-7-7 MDC0014-03-PV-Switch-Installation-Guide-7-7-alt




Installation: commissioning

1. Restore power to the external diverter and Mixergy controller

2. Cancel and schedule heating events/boosts from the Mixergy controller (if active).

3. Set the PV diverter to bypass/boost and check that the immersion is heating via the diverter.

4. Set the Mixergy controller heat source to electric and boost using the gauge; observe that the bypass/boost function of the diverter is switched off and the cylinder continues to heat via. the Mixergy controller supply.

5. Set the exchanger circulator pump speed to setting II for heat pumps, I for solar thermal.


Diverter not working correctly

If the diverter is unable to supply heat to the cylinder, perform the following checks:

  • Check that the cylinder is not entirely full of hot water (i.e. 100% charged). If the cylinder is full of hot water, drain the cylinder down 20-30% and repeat the commissioning steps.
  • Check that the cylinder immersion thermostat is adjusted to approximately 65 C.
  • Check that the diverter is set up correctly according to the manufacturer's instructions.

RCD tripping

If an RCD is tripping when the cylinder is switched on, double-check all mains wiring to the PV switch, diverter and cylinder immersion.

Electrical fault

If an electrical fault of the controller is suspected or the electrical system does not operate as expected, please contact Mixergy directly.

Replacement parts

Part description Part Number
PV Switch PCBA MAS0085
PV Switch enclosure lid MME0144
Pump cable extension MAS0090