Daikin vrv

[eurocooling]

We have a daikin vrv with 11 wall mounted units on we have had a problem with the outdoor boards which we have changed,plus we have done every thing what daikin technical have said to do we have checked compressor,fan motors, trasformers all ok we are now having a code of u4 still coming up which is we know as comuication problem we are still having no led lights coming up on out door board, this system is from 2005 all the indoor wall mounted units come on fans but no outdoor unit or led lights on outdoor unit can anyone help ?

[martinw58]

after fitting new boards did you do reset and test run from out door unit

[install monkey]

u4 No power is supplied to an outdoor,
BS or indoor unit (including
phase interruption).
check all ur plugs connected on the new pcb- check the glass fuses

[install monkey]

if vrv2 then wiring check needs to be performed too, if vrv 3 then auto charge needs to be performed too

[frank]

Check the continuity of the 2core comms wire between all units....it may have been chewed by vermin

[eurocooling]

Hi we have done all this there is no continuity coming from the outdoor board on the 2 core comms,we have tried every thing daikin have said to do

[AbsoluteWDJ]

Questions:

What is the outdoor model number?
Is H3P light on the master PCB?
Do you have the correct Outdoor PCB (part number)?

[eurocooling]

The model number is RXYQ 10M81B there is no h3p light on and the board is correct

[frank]

If you are checking continuity on the wiring have you confirmed that the wiring is intact on the whole f1 f2 circuit?

[eurocooling]

Yes we checked the f1 and f2 thanks for your info

[FreezerGeezer]

I have been told by Daikin (not on a VRF system mind you) that on inverter driven systems the condenser fan motors have on board PCB's. On that occasion, Daikin said the U4 fault meant I had to replace both the cond. fan motors & the outdoor PCB's or else the old remaining one (motor or pcb - doesn't matter which) may well fry the new pcb / fan motor on powering up.

[AbsoluteWDJ]

The model number is RXYQ 10M81B there is no h3p light on and the board is correct

Is there mains power to the new board. You should have H3P light on and H2P flashing when initial mains power is switched on.

[lucapdl]

in all indoor units between f1 f2 have 16 vdc

[kanchi]

Please Press for more than 5 seconds rewiring button of outdoor unit PCB.