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theodore
28-05-2008, 10:24 PM
I'M HAVING A PROBLEM WITH A DAIKIN SUPER MULTI RMX140JZVMB R407C YEAR 2003.

THERE WAS A PCB BURNOUT AT FIVE OUTDOOR UNITS (OUT OF 100 SAME UNITS INSTALLED AT THE SITE).
THE FAULT CODE WAS U2.
WE CHANGED THE FAULTY PCBs.
FOUR OF THE UNITS ARE WORKING PROPERLY.

BUT AT ONE OF THEM THE SAME PROBLEM OCCURED.
[U2 FAULT & PCB BURNOUT].

The Unit Did Not Run At All After The Pcb Replacement Because Of The "u2" Fault. All Connections Were Double Checked.
I Mean That The Unit Did Not Run A Few Days Before The New Burnout. It Happened When We Tried To Start The Unit With The New Pcb!!!

THE POWER SUPPLY IS 232V 49.9Hz. THE BOURNOUT STARTS WHEN THE OUTDOOR UNIT FINISHES THE SEARCH OF THE NUMBER OF INDOOR UNITS ON EACH BRANCH PROVIDER.
THERE ARE TWO RESISTORS OF 39Ω/10W EACH ON THE PCB THAT GET OVERHEATED. THEN THE U2 APPEARS.
THE FOUR PCBs WERE CHANGED THE LAST 10 MONTHS AND THERE WAS NOT A FAULT SINCE THEN.


CAN ANYONE HELP?

superswill
29-05-2008, 12:20 AM
I'M HAVING A PROBLEM WITH A DAIKIN SUPER MULTI RMX140JZVMB R407C YEAR 2003.

THERE WAS A PCB BURNOUT AT FIVE OUTDOOR UNITS (OUT OF 100 SAME UNITS INSTALLED AT THE SITE).
THE FAULT CODE WAS U2.
WE CHANGED THE FAULTY PCBs.
FOUR OF THE UNITS ARE WORKING PROPERLY.

BUT AT ONE OF THEM THE SAME PROBLEM OCCURED.
[U2 FAULT & PCB BURNOUT].

The Unit Did Not Run At All After The Pcb Replacement Because Of The "u2" Fault. All Connections Were Double Checked.
I Mean That The Unit Did Not Run A Few Days Before The New Burnout. It Happened When We Tried To Start The Unit With The New Pcb!!!

THE POWER SUPPLY IS 232V 49.9Hz. THE BOURNOUT STARTS WHEN THE OUTDOOR UNIT FINISHES THE SEARCH OF THE NUMBER OF INDOOR UNITS ON EACH BRANCH PROVIDER.
THERE ARE TWO RESISTORS OF 39Ω/10W EACH ON THE PCB THAT GET OVERHEATED. THEN THE U2 APPEARS.
THE FOUR PCBs WERE CHANGED THE LAST 10 MONTHS AND THERE WAS NOT A FAULT SINCE THEN.


CAN ANYONE HELP?


dont know these systems but does the indoor have a transformer? has this been checked?

philfridge
29-05-2008, 04:31 PM
U2 System Power supply insufficient. You need to get the supply checked properly

theodore
29-05-2008, 08:19 PM
The Fault U2 As You Can See On The Attachment Does Not Refer To Input Power Supply Only. The Detection Is After The Transformation Of Ac/1phase Current To Dc Current

So I'm Not Sure That The Input Power Sypply Is The Problem. The Two Resistors [see Photo] Get Overheated Before The Compresor Start.

1torr
29-05-2008, 09:12 PM
Has the transmision wiring been changed in any way? Could it be f1/f2 or p1/p2 mixed up or polarity wrong.

theodore
29-05-2008, 09:48 PM
It's Not A Vrv. There Are Four Wires From The Outdoor Unit To Each Branch Provider: 1.earth, 2. Phase 230v , 3.communication 4. Neutral