Pressure Testing

Pressure Testing

Once all of the Refrigerant Pipe work has been installed onto your VRF system, you will need to Pressure Test the whole system The Pressure Testing should take place before the system is Powered up for the first time. This ensures that the LEV's (Linear Expansion Valves) in the system will be in the factory position open Following BS EN 378 standards you should use OFN (Oxygen Free Nitrogen) to:

STRENGTH TEST

and

TIGHTNESS TEST

Strength Test

Strength Testing the VRF system is to ensure there are no deformations of joints or pipework and no obvious signs of a leak The pressure at which you Strength Test a sysytem can be calculated using the following:

System Maximum working pressure x 1.1

The system maximum working pressure on Mitsubishi Electric systems is 41.5 bar. This is the setting of the High Pressure Switch This is calculated using the condensing temperature of 55 degrees for R410a gas Therefore.......

45.6 bar

41.5 bar x 1.1 =

Tightness Test

The tightness test is carried out to ensure there are no pressure drops over a long period of time. Ideally the system should be tightness tested for 24 hours. The pressure at which the system is tightness tested is a lower pressure than the strength test

The calculation is: Maximum working pressure x 0.9 to 1

41.5 bar x 0.9 = 37.5 bar 41.5 bar x 1 -= 41.5 bar The tightness test pressure range is

37.5 to 41.5 bar

Make sure to pressurise both the High and Low side of the system to ensure equal pressure both sides of the LEV's