13
Installation: electrical
ENSURE ALL ELECTRICAL SUPPLIES ARE SWITCHED
OFF BEFORE MAKING ANY CONNECTION TO
THE UNIT. ELECTRICAL INSTALLATION MUST BE
CARRIED OUT BY COMPETENT ELECTRICIAN
AND BE IN ACCORDANCE WITH THE LATEST I.E.E.
REGULATIONS.
How the electrical interface works
The electrical interface for indirect/heat pump control on a Mixergy
cylinder works by switching the contacts on a volt free relay.
For heat pump systems, 240VAC must be supplied to the COM
terminal of this relay (terminal L in the HP interface box) in order to
power the included circulator pump.
When the Mixergy cylinder then makes a call for heat, this 240VAC
signal will be switched from the NC terminal of the relay to the NO
terminal of the relay (terminal SW_L in the heat exchanger junction
box). The output on SW_L can then be used to switch a diverter valve
or otherwise interface with the heat pump depending on setup.
The SENSOR1 output can also be used in cases where the heat
pump ordinarily requires the use of a PTC/NTC/PT100/PT1000
temperature sensor for DHW operation.
Use of a temperature probe
In the instance where control of the cylinder by the heat pump is
desired (i.e. cylinder slave operation), a probe pocket is provided to
allow for the installation of the heat pump’s water temperature sensor.
Please note that in this mode of operation, all scheduling and control
features of the Mixergy app will be disabled and the cylinder will only
function as an observational/diagnostic tool. Any scheduling and
control changes need to be performed on the heat pump’s controller.
