Daikin fault

[SkyWalker]

hi guys,

had a daikin u4 fault today, found comms cable at outdoor unit very badly terminated, i re terminated the cable using crimps and thought all would be fine......

upon powering up the system again, i left it for a good half an hour but the outdoor unit would always flash H2P and the green service LED. spoke to daikin tech and they thought outdoor board was bad. what do you guys think.

i ran a new cable for purely communication to eliminate this, indoor unit seemed fine, power fine, green LED blinking on indoor pcb, one thing i thought was strange even when the indoor was thermostat on it wouldnt fault u4 but the outdoor would never start and always flash h2p

put the outdoor in forced cooling via ds1 and it fired up right away??? if i disconnect the comms from indoor it fault u4 but connected it wouldnt.

[Krondor]

Try to Reset the outdoor by pressing the RESET button immidiately after power on
(its BS5 micro button)

[John MacK]

Try to Reset the outdoor by pressing the RESET button immidiately after power on
(its BS5 micro button)


Yes, agree, try a re-set either the button on the outdoor board or short the correct pins if an old unit.

[SkyWalker]

hi guys i tried that but nothing happened, the model was rzq200bw78 super inverter,

[poucapressa]

Where is it in a rzq100b8v3b.
Tank's

[poucapressa]

Where is it in a rzq100b8v3b.
Tank's

The BS5 botton to reset

[acnerd]

If it's a VRV system, are the other indoor units powered up?

[VRVIII]

I think you have taken the model number down wrong the unit will either be an RZQ200B7 or B8 or C7- - .
The BS5 is not a reset button this used for pump down. I would try disconnecting the interconnecting comms cable (terminal 3) at the outdoor unit and leave L&N connected (terminals 1&2) then power up the unit and measure the voltage between terminal 2 & 3 at outdoor unit (confirming comms from outdoor PCB)and then measure the voltage between terminal 2 and the disconnected cable core coming from indoor unit (confirming comms from indoor PCB. Both of these should have a fluctating DC voltage between 10~45vdc. I suspect you will not obtain a voltage from the outdoor PCB confiming the board is faulty.