What sort of electrical supply is needed for the System-S (MCB, RCD spec etc)

Modified on Thu, 18 May, 2023 at 3:37 PM

Supply Requirements:

Outdoor unit = Single Phase C20A 

Indoor unit flow boiler supply = Single Phase B32A

Indoor unit control circuit = Single Phase B13A

RCD Type B protection specified

Any SmartRTC Room thermostats connected to the system can be powered from a Switched Fused connection unit supplying 230v and each SmartRTC needs a Modbus comms cable (shielded twisted pair cable ie Belden 9842 or equivalent) connecting the SmartRTC terminals "A, B & GND" back to the indoor heat pump controller. If multiple SmartRTC room thermostats are installed, the Modbus comms cable must be "daisy chained" from one SmartRTC to the next before connecting to the indoor heat pump controller. A "star" network is not permitted.


Finally, the local Distribution Service Operator (was previously called DNO) must be informed of every heat pump installation. so that they can better plan any network upgrades that may be required in the future:

Connecting electric vehicles and heat pumps to the networks – Energy Networks Association (ENA)

To find your local DSO, enter the property post code on this site: Find Your Electricity Service Operator (powercut105.com)

Further information on this product is available here:


Require additional help? Please follow link below


Applicable to models:  

System S, System S6, System S10, LIA 0608HWCF MS , LIA 0911HWCF MS

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