Economical Best Practice
Air source heat pumps can provide both hot water (providing a suitable DHW tank
is used) and space heating all year. The system is different to a conventional fossil
Important points about heat pump systems
or hydroboxes plumbed to an appropriate storage DHW tank.
However during periods of extremely low outdoor ambient temperature, the im-
mersion heater (if present) can be used for DHW whilst the heat pump contin-
ues to provide space heating. Please be aware that the immersion heater, used
should only be used as a back up in normal operation.
than a fossil fuel boiler.
Overview of Controls
Built into the cylinder unit and hydrobox is the Flow Temperature Controller(FTC).
This device controls the function of both the outdoor heat pump unit and the cyl-
inder unit or hydrobox. The advanced technology means that by using an FTC
controlled heat pump you can not only make savings compared to traditional fos-
sil fuel type heating systems but also compared to many other heat pumps on the
As explained in the earlier section, 'How the Heat Pump Works,' heat pumps are
most efficient when providing low flow temperature water. The FTC advanced
technology enables the room temperature to be kept at the desired level whilst
In room temp (Auto adaptation) mode the controller uses temperature sensors
is regularly updated and compared to previous data by the controller to predict
space heating circuit accordingly. By monitoring not only the outdoor ambient, but
the room and heating circuit water temperatures, the heating is more consistent
and sudden spikes in required heat output are reduced. This results in a lower
should be scheduled using the SCHEDULE function (see page 12). Ideally
this should be during the night time when little space heating is required and
economy electricity tariffs can be taken advantage of.
ture mode. This enables the heat pump to analyse current room temperature
and react to changes in a controlled manner utilising the specialised Mitsubi-
shi Electric controls.
or DHW heating when the property is known to be unoccupied for instance
during the working day.
costs of the system as the heat pump does not have to produce water at very
Flow temp sensor
Return temp sensor
Room temp sensor