18
Combi Hybrids
Operation
In a combi hybrid system, the domestic hot water is heated by the combi boiler and is not heated by the heat pump.
• The heating system is controlled via a thermostat / time clock, the run signal is sent to the heating controls to operate the boiler.
• Whilst the heat pump is running, it will be constantly adjusting the water temperature to suit the ambient temperatures and conditions. This is
the weather compensation of the unit.
• The heat pump will operate on a changeover temperature, this is where the heat pump will stop and a run signal is sent to the boiler to take
over. An example of this would be 4°C and this would be when the heat pump’s output is lower than the required heat input to the dwelling.
• The heat pump operates when the ambient temperature rises above 5°C and resumes normal operation.
• The renewable heat incentive (RHI) will be based on the heat provided by the heat pump only, a heat meter is needed to monitor the input.
A combi hybrid system is were a heat pump and a combi boiler is utilised on the same system. The heat pump is used only to provide space heating and
cannot be used for DHW.
In a combi hybrid system the heat pump and boiler will NEVER provide space heating at the same time.
B
Combi
Boiler
Combi Boiler
must be set to
run at below
65°C
