Malfunction pump of the cooling circuit. You don't feel any vibrations when touching the pump after activating the “Refill mode” via the Communicator software.

1. Check the electrical resistance of the pump winding. Replace the pump if infinite.

2. Drain the liquid cooling circuit, open the pump and check if the pump rotor is not blocked. If so, remove the rotor and clean the bearings of the pump. See service manual chapter "Liquid Cooling Circuit".

Malfunction Fan Control board.

Measure voltage on pump wire while in refill mode. Voltage should be about 20V. If voltage is incorrect then replace the Fan Control board. See service manual chapter "Replacement of a Card Cage board".

Pump end of life.

Replace the pump. See service manual chapter "Replacement of the Pump".