Expansion Vessel
IMPORTANT
Prior to filling the system, the expansion vessel pressure must be set 0.3
Bar below the system pressure. Omitting to perform this check will result in irregular
pressure readings during the commissioning of the system. The pressure is checked
at the base of the vessel and the bleed valve may be bled or topped up with a pump.
Filling the Loop
It is important that a motorised flush and fill centre is used to fill and pressurise the
system with solar fluid as follows:
• Open the fill and drain valves to allow the liquid to circulate around the solar loop
• Close the isolating valve above to the flow meter to ensure all air and liquid passes
through the fill centre to filter any air and contaminants.
• Run the fill centre pump to circulate solar fluid for approximately 60 minutes.
• Open and close the isolating valve intermittently to circulate air bubbles which may
accumulate in the sight glass.
• Return isolating valve to closed position.
• When the solar loop has been purged of air, close the drain connection – the fill
centre will begin to pressurise the solar loop.
• Reopen the isolating valve above the flow meter fully.
• Fill the loop until the pressure gauge just exceeds the required pressure and stop
the pump and immediately close the fill connection. Check pipe joints on the solar
loop for leaks and check that pressure is not lost over a 30 minute period.
• If all the plumbing is sound, set the system pressure by opening the return connec-
tion until the required pressure is met.
• The fill centre may now be disconnected.
• Cap the fill and drain points with the brass covers provided.
Commissioning
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