Close openings immediately after disconnecting pipes and hoses to prevent moisture from entering the system.
Use new O-rings with each assembly.
When connecting pipes, apply lubricant to the area shown in the figure. Do not allow lubricant to get on the threads.
O-rings must be installed close to the tube shoulder.
Tighten the union nut after the tube is fully inserted into the socket (sealing ring is no longer visible).
If a leak is found in the connection, disassemble it and replace the sealing ring, then tighten it again to the required torque.