VRV fault

[Jase]

model no: REYQ20 (combination of 2 REYQ10's)

Fired the VRV up last Friday and left operational. Back on site other day and found unit off on a U2 fault. Reset unit and operated. The system is only operating on the master VRV and the slave has not ran (may not being called for). As I understand, the U2 fault is power related, but all appears normal. Anyone shed any light on this matter?

Jase

[superswill]

what make of unit are you working?

[cool#9]

Jase. This could the official reply by Daikin:
< VRV >
What U2 (Over-voltage Detection) ?</B>System
Power supply insufficient. Check power supply.
[ Supposed causes ]Power supply insufficient
Instantaneous power failure
Open phase
Defect of inverter unit
Defect of outdoor PCB
Defect of 52C1*
* G, H Series = 52C1, K, L, M Series = K1M
Defect of main circuit wiring
[ Check point / Remark ]Turn 52C1* ON
The voltage between the P2 and P1* terminals must be
350 VDC** or more when the compressor is running
* G, H Series = P2 and P1, K, L, M Series = P and N
** G, H Series = 350VDC
K Series = 361VDC (Y1, YAL), 209V (TAL)
L Series = 320VDC, M Series = 380VDC Turn 52C1* not ON
200V ~240V** of power is reaching the 52C1*
** G, H Series = 52C1, K, L, M Series = K1M
* G, H Series = 200V ~ 240V
K Series = 380V ~ 415V (Y1), 380V (YAL), 220V (TAL)
L, M Series = 220V ~ 240V
(5) The voltage between P2 and P1* gradually rise to 560DCV*
after turning on
* G, H Series = P2 and P1, K, L, M Series = P and N
** G, H Series = 560VDC
K Series = 537VDC (Y1, YAL), 311V (TAL)
L Series = 339VDC, M Series = 556VDC
220V ~ 240V* of power is reaching CN23** of INV PCB
* G, H, L, M Series = 220V ~ 240V
K Series = 380V ~415V (Y1), 380V (YAL), 220V (TAL)
** G, H Series = CN12, K Series = X1A
L Series = X5A, M Series = X1A
200V ~ 240V* of power is reaching CN5** of outdoor PCB
* G, H Series = 200V ~ 240V
K Series = 380V ~ 415V (Y1), 380V (YAL), 220V (TAL)
L, M Series = 220V ~ 240V
** G, H Series = CN5, K Series = X5A
L Series = X5A, M Series = X1A
in addition...

Also you'll find attachement.
The problem is to find what VRV is faulty. It's not so easy and i'll try to explain later because i'm going to bed...
Regards
cool#9

[Obi Wan]

Hello Jase,

The U2 fault is mainly due to incorrect power supply. Check from the distribution board to the terminals on the outdoor unit. There may be a loose connection one of the phases. Also check the contactor on the outdoor unit K1M is operating.
U2 is displayed when the capacitors on the inverter PCB are not charged up sufficiently prior to the inverter compressor starting.

How did you reset the system? If you switched Off all the indoor units from the remote controllers and switched them back On, then the system is operation in the “Back up” mode. The outdoor units that generated the fault is not operated for 8 hours. After that the unit is put back into operation and if the fault is still there it will trip again. This back up mode is only operational when you have a multi outdoor combination. i.e. you don’t get it on single outdoor unit installations.

To reset the system correctly you will need to power down both outdoor units. Don’t forget you will have up to 15 mins wait for the system, to re-initialise.

Let us know what you find.

Obi Wan

[alexdouglas1969]

Hello mate

Check the condenser fan motors and fuses on the PCB we've had a few motors pop due to water ingress, turned out there was a batch of faulty motors - the windings were not sealed from the rain. Obviously the Daikin techs stick with the official fault diagnosis. Was this just after a rainy spell?

Cheers

[DEVIL]

hello

U2 could allso be caused by a problematig fusible fuse, in a'n old building it is possible to have somwhere up the stream some old one that could cause a problem like that

[Jase]

Thanks for those replies fellas!
Back to site tomorrow as I have to fit the ITC. That should be fun!
I will carry out a thorough check on this problematic system. Is there another way of forcing the slave unit to ON other than force the system ON by means of test run function by means of the buttons on the master unit?

Thanks in advance,
Jase

[Obi Wan]

Hi Jase,

There are two ways to get the slave unit to start first.

1, There is a starting priority order on the VRV II /III multi outdoor systems. On the 1st start up the master outdoor unit will start first, then the Slave 1 unit and so on. When the system stops i.e all outdoor units stop, and then start up again, then Slave 1 unit will start first. So if when you start up the system and the master unit starts up first, all you have to do is to switch off all indoor units on the remote controllers and then switch them on again, this time the Slave 1 unit will start.

2, Use the programming buttons on the master unit to put the master unit into “emergency” mode. This will disable the master unit and only run the slave units.
(Setting mode 2, item 38)

Hello mate

Check the condenser fan motors and fuses on the PCB we've had a few motors pop due to water ingress, turned out there was a batch of faulty motors - the windings were not sealed from the rain. Obviously the Daikin techs stick with the official fault diagnosis. Was this just after a rainy spell?

Cheers

Hello Alexdouglas1969

I think you are confusing the VRV K series with VRV II. VRV II has an inverter driven fan motor and did not suffer from the problem you describe.

Regards

Obi Wan.

[Jase]

Checked both VRV's today. Powered down units and crimped the incoming wiring. Checked all connections on pcb's.
The master unit connections appeared to be normal.
As I removed the panel to gain access to the inverter pcb on the slave unit the connection X6A was out, so reconnected.However, I think it pulled out when I pulled the panel away to gain access.
Powered up units and checked incoming voltage. All normal, no imbalance.
Initiated test run from the master unit and system tripped out instantaneously. Powered down system once more and reset. Switched all 8 fan coils on @ remote controllers and master unit operated. Left operating as had to leave site to attend other job.
So, it may be that I have a fault with the slave unit. Agreed?

Regards
Jase

[DEVIL]

iup, it may be, u could test that by runing the slave unit, widouth the inverter compressor, if u say it tripped on the begining of the test, it must be the inverter compressor &/or inverter PCB and u cand do that by settings on the master unit, and then u know for shore, but u should allso check the mains on the slave unit, as they should have separate power cables (the master and the slave unit)

[Jase]

Replaced the inverter pcb on the unit which solved the problem.
Noticed on the faulty pcb that a couple of the capacitors had 'popped' out at the X mark on capacitors.

Cheers
Jase