System design requirements

System design requirements

The heating system should be designed to maintain 70% of the nominal flow of the system across the heat pump at all times.

Underfloor heating systems should have at least half of the coils fully open at all times.

Alternatively, or where TRVs are used a by-pass may be fitted. This must still maintain 40% of the nominal flow across the heat pump.

Where it is not possible, due to the design of the heat emitters, to maintain this flow rate a Worcester primary store of around 100 litres should be fitted.

system layout

Connecting the heat pump to the heating system

Care should be taken to avoid excessive use of flux on copper pipe connections to minimise the amount of debris and blocking of the filter.

System flushing and care

Central heating systems must be flushed before the heat pump is installed. The system should be prepared in accordance with the guidelines of BS 7593 : 2006.

The filter on the primary circuit should be checked during the first week of operation to ensure that any debris is removed.

It is important that all previously mentioned preparations have been carried out before the heat pump is connected to the heating system. Also ensure the pipe system has been well flushed before it is connected to the heat pump. Flushing protects the heat pump from contamination.

The heat pump is a part of the heating system. Faults in the heat pump can be caused by poor water quality in the radiators or underfloor coils or because air is penetrating the system continuously. Oxygen causes corrosion products in the form of magnetite and sediment. This is detrimental to the heat pump components and reduces their working life. Existing heating systems which require regular filling or where the heating water is not clear when drained, require cleaning and flushing before the installation of a heat pump, for example the heating system must be fitted with filters and vents.