Daikin u1 fault?

[airconadam]

hey again fellas just a quick one really, found a unit on maintenanace today which was faulting u1 (reverse phase) but how does it become reversed and how to solve it? do i just swap ie u1 with v1 or vice versa or w1 with u1 if you know what i mean thanks alot

adam

[Brian_UK]

Check that there hasn't been a failure of one phase.

As far as reversing the phases - it doesn't matter which two wires you change.

Q: "How do the phases become changed" - Ask if any electrical work has been done within the building. Often you will find a new distribution board has been fitted or something similar and the electricians have had cause to do some re-wiring.

Worst case is the local electricity board has changed phases outside.

If you change it listen to the compressor if it is a scroll - lots of noise and no suction equals wrong rotation.

[multisync]

Check that there hasn't been a failure of one phase.

As far as reversing the phases - it doesn't matter which two wires you change.

Q: "How do the phases become changed" - Ask if any electrical work has been done within the building. Often you will find a new distribution board has been fitted or something similar and the electricians have had cause to do some re-wiring.

Worst case is the local electricity board has changed phases outside.

If you change it listen to the compressor if it is a scroll - lots of noise and no suction equals wrong rotation.

But Brian as you know because it's a Daikin it won't run backwards so he'll never know.. best try it with an 407c LG as they didn't come with phase rotation :-/

Multisync
London

[Brian_UK]

But Brian as you know because it's a Daikin it won't run backwards so he'll never know.. best try it with an 407c LG as they didn't come with phase rotation :-/

Multisync
LondonVery true, slapped wrist time:p

[frank]

I had a U1 fault some years ago, but, every time I got to the machine and reset it, it worked no problem.

After half a dozen call outs, I just happened to have my meter on the incoming mains when the Blue phase dropped to 134volts momentarily. It was enough of an imbalance to cause the U1 fault but then it was measuring 240 again.

I reported this to the electricity company who investigated and they found a partial break in the supply cable under Barclay's Bank some 5 shops up the road.

I got a couple of Brownie Points for that :D

[airconadam]

hey fellas thanks alot for your thoughts and solutions will check it out proper tomoz and let you know the outcome thanks alot

adam

[Obi Wan]

hey again fellas just a quick one really, found a unit on maintenanace today which was faulting u1 (reverse phase) but how does it become reversed and how to solve it? do i just swap ie u1 with v1 or vice versa or w1 with u1 if you know what i mean thanks alot

adam

Hi Airconadam,

You mention the terminals U1,V1 & W1, there terminals are normally at the compressor end. Don’t change these cables. You need to swap the mains incoming cables on terminals L1,L2 & L3 or if really old kit then R,S,T.

Regards

Obi Wan

[airconadam]

hey obi wan your correct the cables was L1,L2,L3 after looking in the outdoor today i found a fuse blown which was f1u i replaced this and tried to run the unit up but still faulted on u1 straight away?? i then tried to switch the mains power ie L1 with L2 coming in but still faulted u1, i checked the comp wasnt to earth tried running the unit without the compressor connected but still no avail. not sure what has caused the fuse to blow and wondering if it is a problem with the outdoor board will ring daikin tommorrow but hopefully one of you fellas can help thanks alot

adam

model No-Rp71b7w1, 3ph, R407c

[Brian_UK]

Fuse F1u feeds the PCB transformer, the indoor unit, control signal transmitter/receiver and the reverse phase detector.

It would seem that the reverse phase detector has gone or the board itself has gone.

This is assuming that you do have three phases available.

[airconadam]

yes brian all 3 phases are there the indoor unit will run but fan only. The outdoor board also looks like it has been very hot at some point aswell not the best of signs thanks alot

adam

[Brian_UK]

Might be worthwhile pulling the board and having a look at the back of it.

Amazing the burnt tracks and fried spiders that you can find behind there ;)

[Kaiser]

Last U1 fault I had on a Daikin Ducted was outdoor PCB Fault, visual inspection showed damaged components.