Daikin VRV II Test Mode Failure

[KISS KISS BANG]

Hi All,

Just wondered if anyone has encountered the problem of VRV II systems (2 Pipe) failing the initial refrigerant check function for no obvious reason. The first time this happened to me I imediatley put the Service Checker on and proved the system to be running fine. I later found that if the system is run in full heating mode for 20-30 mins before running the test procedure, it passes the test straight away. Daikin say that the 1st test often fails anyway but the second one should pass (assuming there's no wiring errors obviously) but Ive had some systems which never pass the test but perform fine.

[puddleboy3]

Can you tell us when the systems fail the test what fault code is shown. Also on the outdoor board when running in the test cycle. The orange leds light at certain points of the test, if you could let us know at what stage it fails then this would be a big help The only thing i cant work out is how you can get the system to run in heating mode before the test procedure the system should display U3 until forced through its test? I know that if you start the test cycle and then ditch the power and turn back on then it will not display the U3 but this can give more problems as the system can not work out its pipe length and if its refrigerant level is correct. Im going to have a guess at F6 fault and its displayed after you have added the additional charge to the system and running for the first time!

[KISS KISS BANG]

Fault code displayed after test fail is "UF". The error code is not displayed untill the test procedure is completed (approx 20 mins). I get the system to work in heating mode after the test has failed by bringing the system out of test mode first. This is done by pressing and holding down the "Return" button, This can be done at any time during the test procedure but I always wait for it to finish. F6 fault is never displayed as this would relate to high discharge temp but there is not actually any problem with the systems - they all works fine. The idea of the test is to check for closed service valves, refrigerant overcharge and to check that the indoor unit its piped to are the same indoors it's wired to. At the moment I'm going to put it down to the fact that the test is unreliable on systems with longish pipe runs and hopefully further testing will prove this.

[puddleboy3]

Fault code displayed after test fail is "UF". The error code is not displayed untill the test procedure is completed (approx 20 mins). I get the system to work in heating mode after the test has failed by bringing the system out of test mode first. This is done by pressing and holding down the "Return" button, This can be done at any time during the test procedure but I always wait for it to finish. F6 fault is never displayed as this would relate to high discharge temp but there is not actually any problem with the systems - they all works fine. The idea of the test is to check for closed service valves, refrigerant overcharge and to check that the indoor unit its piped to are the same indoors it's wired to. At the moment I'm going to put it down to the fact that the test is unreliable on systems with longish pipe runs and hopefully further testing will prove this.

Well thats a new one on me with the return button. F6 relates to abnormal reciever temperature not high discharge temp which is F3. Ive commissioned over 100 VRV II three pipe and two pipe systems with long pipe runs and even systems that have been over there limits and refnets installed in correctlly with no major problems, think there may be something your missing at commissioning procedure.

[KISS KISS BANG]

So you're saying you've NEVER had one fail the test??

I'm probably comm'ing about 40 per month at the moment and about 1 in 10 fail the test 1st time round and the odd one never passes the test at all. I always add the correct additional charge from a vacc, always triple vac, always vac to at least 2 Torr and always perform a rise test so I don't think I can be missing anything out. The problem seems to be unique to the M9 series but not the M8's. Daikin have no answers either but that's nothing new!!

[puddleboy3]

Must admit the majority of the units i commissioned were the M8 units with the oil equalsing line and any time i had a test fail it was due to installation error crossed pipes or me having a bad day and leaving a valve closed!

[chiller-man]

Just, commissioned a VRVIII 3 pipe, I thought by now Daikin would have got rid of those dam stupid yellow led's and at least fitted a 7 segment display, and as for the manual, well who ever translated it into english needs to go back to school. We are a D1 installer and the next time I see our rep I will be telling him we will not be installing any more of this crap!
Give me a Hitachi Set Free any time!

[rahul varshney]

hi everbody,

I need a help from you all experts. I am going to install a Centrally AC unit in my hotel project, which is 44 rooms property including banquet, bar, restaurant, reception area, office area etc. Would you suggest me to go with Daikin VRV III ? I would like to know in detail. Thanks in advance.

[Mentallist]

UF error is indicated during the test operation when 1 or more indoor unit coild temperatures does not drop during the test. When the test is in operation, an initial evaporating target of -15 degrees is set. The system then checks to ensure that all indoor coil temperatures drop. If 1 or more doesnt, the error code UF is generated. There may be a number of reasons for an indoor unit coil not dropping - (No refrigerant flow - Stop Valve closed - Indoor EXP valve not opening - Cross piping/wiring). I would advise connecting your checker and activating the test operation once again. This will allow you to note the abnormality. The software for VRV II systems allowed operation of the systems without the need to complete a test, but it is important that one is completed to allow the pressure drop to be calculated and the automatic piping length judged by the system.