Full details are available in the Operation and Maintenance manuals supplied with the product and can be downloaded here. It is important that the manual is read before any installation begins.

The headers or tails of each slinky should be returned to one common point, (usually on the side of the building) where they are connected up to form a single flow and return to the heat pump. This is termed the slinky manifold. On larger commercial installations intermediate manifolds may well be required, these are termed header manifolds. Kensa can supply slinky and header manifolds, which are suitable for all system sizes.

The manifold for the slinkies should be placed on the outside wall of the building, ideally with the heat pump on the other side of the wall. This is to avoid having to insulate the manifold with vapour barrier insulation to prevent condensation. It also reduces the number of entry/exit holes in the building’s fabric. Once installed an enclosure can be built around the unit if required, or if a heat pump is decided on early in the project a recess can be designed into the external wall.

On the slinky manifold, each end of each slinky connection is terminated in a 32 mm to 28 mm reducer, which is connected to a 28 mm compression valve. Each of these valves is connected to either a "feed header" or "return header". It is important that the effective length of each slinky is the same, to ensure even flow rate across them all. Each manifold also contains a purge connection, which is used to initially fill the slinkies and purge them of air.

Connecting Slinky pipe to the manifold

The slinky pipe must be cut squarely and neatly, and any burrs inside or outside removed. An appropriate plastic pipe cutter should be used. Each slinky manifold is supplied with copper ferules, one of which must be inserted into the end of each slinky pipe. This avoids the plastic pipe from being crushed by the compression fitting. It is essential that the slinkies are the same length to ensure even water flow. The slinkies are all supplied as identical lengths - do not cut them to different lengths exceeding +/-1m. The slinkies should be connected to the manifold in a reverse return configuration to ensure that they are kept to the same length i.e. if slinky A is connected to the furthest connection away from the flow connection to the heat pump, it should also be connected to the connection closest to the return connection from the heat pump on the return side.

Connecting the manifold to the heat pump

All 1, 2 and 3 way Compact Heat Pump slinky manifolds are supplied with 28 mm ‘Speedfit®’ push-fit connectors and are universal, i.e. can be configured on-site as right or left-handed. Other Compact Heat Pump manifold sizes are supplied with 50mm connectors and need to be specified as right or left handed at the time of ordering. Plantroom system manifolds can be larger sizes.

Connection to a Compact Heat Pump should be via 28mm ‘Speedfit’, 50mm MDPE/HDPE or similar plastic pipe systems. This pipe can be purchased from any plumbers’ merchant. The maximum distance between the heat pump and the manifold is 20m. If the distance is greater than this please contact Kensa for further details.

2 way universal manifold (set for left handed)	4 way ‘left’ handed manifold

Any ground pipes inside the building should be insulated using a vapour barrier insulation, such as "Armaflex" to prevent dripping from condensation. Any pipe outside the building need not be insulated since the circulating fluid contains anti-freeze.

Purging of the slinkies and adding antifreeze.

Purging the slinkies of air is vitally important for the correct operation of the system. If air remains within the system this will cause the heat pump to rapidly freeze. While this will not damage the heat pump, it will cause the unit to stop operating and no heat would be provided to the building.

Removing the air from the top of each slinky loop can be difficult. The slinkies consist of a large number of 1 metre diameter loops of 32mm of pipe. Even vertical (ie. drilled) arrays can have trapped air. All the information about removing air from slinkies applies equally well to removing air from underfloor heating systems—which is why almost all underfloor heating manifolds have fill/purge connections, and the same pump and procedure can be used for both.

The longest slinky trench should be 50 metres, which will contain a total of about 300 metres of pipe. To achieve the minimum velocity through the slinky pipes to remove the air, a certain size of pump is required. The power absorbed by the pump will be over 1 kW. So, if you are considering using an existing pump that you may have, if it does not absorb at least 1 kW then it will not be suitable. We recommend the Clarke CPE130SS as the most suitable pump and his can be ordered from Kensa as an additional extra.

The pump comes complete with a 1” BSP Male Iron to 28 mm compression fitting. This will enable the pump to be connected to the slinky manifold using 28 mm Speedfit or similar pipes and elbows.

For full details on how to purge the slinkies please see the Operation and Maintenance manuals.

Once the slinkies are purged of air, the antifreeze should be added slinky by slinky. Again for full details please refer to the Operation and Maintenance Manuals.

All supplied antifreeze should be added to ensure protection from freezing.

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