Technical data

22
5. Commissioning
After all mechanical and electrical work has been completed, the following commissioning instructions
should be followed.
5.1 Purging the ground array of air.
It is important for correct operation that all the air is removed from the ground arrays. Slinkies consist of
a large number of 1 metre diameter loops of 32mm OD pipe and air can collect at the top of these loops.
Even vertical (ie. drilled) arrays can have trapped air and should be purged.
To remove the air from ground arrays, a suitable pump will be required. For slinkies, the longest slinky
trench is 50 metres, which will contain a total of approx. 300 metres of pipe. To achieve the minimum
velocity required to remove the air, a minimum pump power in excess of 1 kW is required. In addition, the
pump needs to have a flow of at least 60 litres per minute against a pressure of at least 1 bar. To achieve
this, a multi-stage pump is required.
A normal rising cold water main in a building has insufficient flow to force out this air. Mains water is also
“aerated”, so should not be used.
The recommended purge pump is the Clarke CPE130SS (part no. 051010379). The pump is supplied ready
to take a 1” BSP fitting. Two x 1” BSP male to 28 mm compression fittings are required to enable the pump
to be connected to the slinky manifold using 28 mm “Speedfit” or similar pipe and elbows. These are
readily available from plumbing merchants.
The Clarke CPE130SS can achieve as much as 5 bar pressure against a closed valve, so ensure the
connections to the pump and manifold are robust.
5.1.1 Purging Procedure for Multiple slinkies (for single slinkies, see section 5.1.2)
i. Remove the plastic blanking plugs, and connect the purge pump to the fill and purge ports on the
Slinky manifold, see diagram over leaf. Keep the isolating valve to the heat pump closed. The purge
ports can be connected either way round.
ii.
Connect the purge pump to draw from an 80 litre dustbin half filled with clean water. This pump
must be capable of circulating 60 litres per minute against a pressure of 1 bar. If the pump’s
electrical rating is less than 1 kW, then it is unlikely to be suitable. Vent-Axia only recommend the
use of the Clarke CPE130SS pump as above. The water level in the dustbin will need to be topped up
constantly during the following process. The pump may need priming by pouring water into its
priming port until it overflows.
Fig 20 Clarke
CPE130SS Purge
Pump