View Full Version : help please

26-01-2011, 08:58 AM
Hi forum

I have just had a 20 kw invertor installed
but the guy has had trouble getting it working

he said he would come back thursday but
today is so damm hot

it is displaying a U3 error
I think this means it is not commissioned

how do I fix it?


26-01-2011, 09:03 AM
Hi jabela

It might help the members if you posted some details about your system, such as, Make, Model, Number of indoor units, Number of outdoor units, Refirgerant type etc.

From where we are, we cannot see your system.

26-01-2011, 09:26 AM
Thanks for the prompt response
it is a daikin
3 phase
ODU is RZYQ8PY1 (built 9/2010)

just installed yesterday

U3 error keeps coming up

from my reading it may not have been commissioned?
i am not sure what this means
is there a process of comissioning
I can not find an operations manual


26-01-2011, 09:29 AM

there are 11 outlets
on 2 zones

i gather i press the zone 1 and 2 till the green LED is displayed, and hence they are usable


26-01-2011, 03:45 PM
The U3 error means that the system has not been properly commissioned.

I would get the installer back to complete the job properly.

The are a number of settings/checks to do, in addition to adding any additional refrigerant, prior to carrying out the test operation.

The attached pdf explains how to carry out the test operation

26-01-2011, 11:31 PM
Beware of voiding your warranty by playing with a non-commissioned system.

It might prove expensive if things go wrong or you extend the commissioning time and the technician has to start again because of your actions.

27-01-2011, 03:31 AM
I installed one of these last November and they take about an hour and a half to commission properly.

27-01-2011, 10:51 AM
Thanks for the suggestions. A different guy came back today
And tinkered for a little while and commissioned the unit

He could not understand why the first guy could not complete the job

All worked well for about 2 hrs
Then it stopped working
And started to display the error code LC

Anyhow. The guy is coming back
Again tomorrow.

What does it all mean.


Thanks for the responses

28-01-2011, 12:31 PM
Hey all

Another guy came back today
And fixed the problem

The problem was that one of the 3 phases had a dodgy connection
It was intermittently connecting and disconnecting

The guy today found the wire responsible and secured it
And took some photos to stir up his mate about a dodgy install

The guy explained that without the 3 phase working the unit could not go through commissioning, and hence the u3 error. The yesterday must have been lucky enough to be able to commission the unit while there was a temporary connection. Then after a while the 3rd phase was lost and hence it became a LC error.


With the wire secured, all is perfect.

Thanks all for your (collective) help


28-01-2011, 06:50 PM
I took a leaf out of this guys book. Last year I was working with and Airedale tech who was comissioning 2 close control units I'd installed.
First thing he did was check every terminal was tight in the electric panel.
No loose wires but later found that the pressure sensors connected @rse about face on the terminal block.:o