Electrical support

Support with connecting a Mixergy cylinder to work with a gas boiler, heat pump and timer controls

What wiring is required to install a Mixergy cylinder?

A Mixergy cylinder requires a mains voltage electrical supply. Mixergy cylinders must be connected to a dedicated 16A MCB-protected circuit via a 20A DP switch and be wired to the latest IEE wiring regulation. A qualified electrician is required to make an electrical connection to the unit.

How do I wire the Mixergy cylinder to work with a gas boiler?

The Mixergy cylinder uses a 4-core cable (labelled “indirect control cable”) to energise the two-port valve to call for heat. The black wire of the indirect control cable connects to permanent live, the brown wire sends the “hot water on” signal to energise the two-port valve, and the grey wire sends the “hot water off” signal to the three-port valve if it is a Y-plan.   

Note: if you cannot detect a live signal for the brown wire when calling for heat, first make sure that the cylinder’s heat source is selected as “indirect, e.g. gas boiler”, and then check if the thermostat has been tripped. 

How do I install the heat pump interface switch?

The heat pump interface is a device designed to allow for a generic interface with heat pumps expecting the use of a digital NTC/PTC/PT100/PT1000 style sensor to detect and control the hot water temperature within the cylinder.

The heat pump interface has a pre-set range of resistance values for most common heat pumps and a manual resistance setting option. This ensures that the cylinder can communicate with any heat pump. The interface also negates the need for a dedicated stat pocket for the heat pump. Full details of how to install the heat pump interface can be found in the Installation Guide.

Do I need another power supply for the heat pump interface?

You can either take the power supply for the heat pump interface off the cylinder’s primary supply or provide an external 3A supply (either from the heat pump’s controller or elsewhere). This supply is used for powering the board’s electronics and 40W pump.

How do I connect to a conventional or smart water timer?

The Mixergy controller has a cable labelled ‘timer control cable’, which allows you to hard wire a 240V switched live connection from a smart thermostat. This enables the third-party thermostat (HiveNest, etc.) to send a call for heat to the Mixergy cylinder. If you boost the Mixergy cylinder through the smart thermostat for a 30-minute hot water event, the cylinder will respond to the call to heat for 30 minutes before returning to the Mixergy set schedule.  

The third-party timer controller can control hot water heating by time only – not by volume. These controllers will also not enable you to maintain a particular hot water level. Therefore, we encourage all Mixergy users to programme and control their Mixergy cylinders through the Mixergy App to get the best user experience.