Leak test on a Mitsubishi Electric power inverter split air conditioning system

Carrying out a refrigerant leak test on a Mitsubishi Electric power inverter split air conditioning system after we diagnosed the system to be short of refrigerant gas on a bi annual maintenance visit.

Firstly we had to reclaim the remaining R410a refrigerant gas within the system, we pressure tested the system to 35 bar using oxygen free nitrogen and sprayed all accessible joints with Gotec leak detection spray.

After a visual inspection on the indoor unit, we found that the lagging around the 5/8 flare connection was covered in refrigerant oil and the leak was confirmed when we sprayed the joint with the leak detection spray and it began to bubble.

We replaced the flare nut and remade the flare connection before pressurising the system again to 35 bar with OFN and dehydrated the system to 2 tort with a vacuum pump. Once a 2 torr vacuum and rise test was achieved then the system was charged with virgin R410a refrigerant gas to the manufacturers specified weight.