What are the typical installation requirements for System-S?

The manufactures instructions for the System S heatpump must be followed. Below is a link to the instruction manuals which must be read and adhered to prior to installation of this product.

On a typical installation, there will need to be:

-    Mains supply for outdoor unit and two mains supplies for indoor unit (controls + power for 6kW backup flow boiler).

-    Comms cable (Modbus) which can be Belden 9842 or Equiv shielded twisted pair) going between indoor & outdoor unit

-    A pair of insulated refrigerant lines going between the indoor & outdoor unit.

-    Inside, there needs to be a low-loss-header "parallel" buffer tank at least 25L for 6 & 10kW installs. 

-    A temperature probe located on pipework after the buffer (R2.2) where parallel buffer / low loss header is used.

-    Pipework from the low loss header to the heat emitters (radiators or underfloor heating) and from the indoor unit to the buffer.

-    SmartRTC room thermostat(s) highly recommended to control system efficiently. Also possible to use weather compensation.

-    Cold water feed for the indoor unit (for the hot water tank)

-    G3 unvented pipework & heating circuit vent pipe

-    Ideally, a CAT5/CAT6 Ethernet cable going from the indoor unit to the intended broadband router location or central network switch in the property so that the heat pump can be connected to the internet.

Inside, there is a minimum room size required for the indoor unit as the System-S contains R32 refrigerant. It is up to the installer to ensure the product meets that minimum room size requirement. See section 5 of the installation manual for room sizing information.

Outside, the heat pump needs to be located so that condensate can drop out into a suitable soakaway, that the heat pump is located in a way to allow free airflow (see install manual for clearances required) and that the heat pump is located so that it minimises potential noise to bedrooms or neighbours. 

The heat pump needs to be in a location that is accessible for servicing (wall mounted above head height is not the case!)

Finally, there is a maximum 15 metres refrigerant line distance between the indoor and outdoor units permitted for a standard installation. 

Related questions which may also be useful:

Where can System-S be installed & what are the installation limitations?

"How far away can the outdoor unit be situated from the indoor unit? Topping up R32 if over certain distance..."

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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