Myself and Maico were able to top up the NHC window oil.

The oil was filled through the expansion tank

- the Nitrogen line closed and the Nitrogen pressure valve was disconnected to ensure that no oil would go in to them.

- the pressure relief valve was disconnected to act as an air bleed line while we filled the oil

- with a funnel we slowly added the oil until the oil level could be read, showing about half full

- about 1.5 liters of oil were added

- once filled the Nitrogen line was reattached and the pressure was returned to recommended level 

- the remaining oil was returned the RH shop

Now the oil level will be monitored, which will help identify if there is any leak in the system.