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5.1.4 Pressure Testing in accordance to BS805 Section 11.3.3.4
In accordance with MCS Guidelines, leak tightness (pressure) testing has to follow the EN 805
prescriptions in section 11.3.3.4. This test should be carried out after the ground arrays have been purged
but before the antifreeze is added. For polyethylene (PE) tubes, the pressure testing has to be carried out
as a 'compression test'. An overpressure (inside-outside) is applied to the pipe over the whole length. This
step inflates slightly the PE pipe over its whole length. Then a sudden pressure drop of around 10% of the
testing pressure is applied. This pressure drop allows the pipe to compress again. If the pipe is tight, a
pressure increase is measured. This test should only be carried out on the ground arrays with the heat
pump isolated from the test.
To perform such a test, the following equipment is needed:
•
A high-pressure pump or a manually operated pump
•
2 stop valves
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1 manometer 0 -16 bar
•
A de-aeration device (if any point of the ground array is at a high point where air can collect)
Test procedure in detail (Fig. 14):
•
1 h Idle period. No overpressure is applied to the tube .
•
Apply the test pressure. For PE100/PN16/SDR11 ground arrays this should be > 7.5 barg. If the heat
pump is within the pressure test this should be less than 10 barg. For other materials follow the
manufacturer's specification
•
10 min Keep up pressure test
•
1 h Idle period. The tube is going to expand over the whole length
•
Pressure measurement. The pressure drop may not exceed the manufacturer‟s specifications
•
Sudden pressure drop of at least 10% of the test pressure
•
10 mins. First pressure measurement
Plant Room Heat Pump Manual Version 11.1
Page 21 of 34
A
Fig 13 Leak Tightness
Configuration
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