Daikin u4 error

[Mindreader13]

I have a daikin split inverter ac and I was good for 4 yrs. Recently, it runs ok for few hours and then stop with light blink. Then I checked from the remote and got u4 error. If I let it sit for few hours and turn it back on, it can run for few hours and stop again. Anyone know what is the most possible cause of my a.c.?

[hyperion]

U4 can be caused by a communication problem between the indoor and outdoor unit. There could be a bad electrical connection on either of the units. There may be some localised interference affecting the interconnecting cable.
Have you tried turning off the power to the unit, as this should then reset the system and might clear any interference.

[install monkey]

external tank pump limit switch breaking live to 1 of the indoors thus generating the u4 error

[Greek_engineer]

Can you provide further information or illustrated instructions?
Daikin says that the u4 fault can be diagnosed with the use of a electrical wave meter,I mean checking the power supply wave.

[Mindreader13]

Hyperion, if I just turn off the turn back on, light will blink again. As mentioned, I need to let the ac sit for few hours and then it becomes ok for few hours.
More investigation, if I don't turn it off and let it sit. I will be on again automatically.

Install monkey, I don't quite understand what you mean. Could you explain more?

Thx everyone

[Mindreader13]

Some ac technician came and he said that problem can be cause by the board or motor. But the replacement cost is like almost buying a new one. Also, he said that my a.c. Electrical wire are going through the insulator and that might cause the problem too.

Also, i noticed that it seems if outside is hotter, the light blink sooner and seems need more time to sit to be on again. So now, anyone can suggest me what to do.... Very frustrated now