ROTEX HPSU / DAIKIN ALTHERMA 11kW "ERROR U2"

[v.k.]

Hello Experts!

Having problems since NOV-2010 with my ROTEX HPSU units. Outer unit's fan starting up 30 secs. and then shutting down. Display on inner unit showing Error-Code U2.
System is from now on running only on immersion heating element.

After restart or reset of fuse same procedure.

ROTEX told, that compressor in outer unit can not started, so they replaced board in internal unit but are clueless now, as error is still shown...

Any ideas??

[Brian_UK]

Some Daikin fault codes...

http://www.orionair.co.uk/daikin%20skyair.htm

[install monkey]

altherma fault codes differ from standard daikin fault codes =U2 Abnormal Inverter Circuit Power Supply Check power supply, check bridge rectifier, check fan motor, is inverter input voltage approx >280Vdc

[brunstar]

It is important that the capacitor is connected correctly on the DC side of the inverter circuit, if this is incorrect the wave form will be incorrect and this error can occur with a new printed circuit board installed. the colours are grey and orange. Make sure that the reactor is connected with a good connection these are 2 x white cables.

If there is still a U2 fault then the problem can be that there is low voltage to the unit, the outdoor fan motors or compressor can also cause this, start with metering the compressor resistance and input voltage to the unit on start up.