Daikin vrv 3 pipe problem

[licencetochill]

Hey guys,

I have a vrv system we have been asked to look at , its an
Daikin Rny8ky1, and two rxy8ky1. feeding 12 fxys63kv1 ducted indoor units. R22.

Half of the floor seems to not perform, Yesterday it was 25 deg, i put all the indoor units into cooling 18 deg.
Only the inverter compressor was running, No fault codes..
Seems like a comms issue but normally id expect a fault..
Dont think its short of Refrigerant, but there is no info on the units as towhat th pipe run lengths are..
I bloody hate vrv, so i dont really have much to do with it.
Any help would be cool

cheers

[El Padre]

Hi,

Here in the UK we can phone Daikin and they are normally quite good at sending out the manuals, you could also try the extranet but people have been having access problems recently.

You can use the buttons on the outdoor board ( I think its binary 5)to give a thermostat on signal, and then check your indoor coil temperatures in code 41 on the local controllers.

I think that the above procedures are in all of the VRV manuals.

Regarding refrigerant shortage, discharge temp/superheat is always a good indicator of refrigerant shortage.

Cheers

[ktm]

Yea sounds like short of gas. Don't think the other outdoors will ramp up. Was the inverter running 100%? Could u get the commisioning report of the customer and find the added charge?

[martinw58]

the standerd compressor may be switched off from the buttons on the outdoor board but it sounds like short of gas

[Mentallist]

The system you have is an R22 VRV+ so you must have a function unit with it also. The 3 modules you described are as follows: RXY contains 1 x inverter compressor and 1 x standard compressor, the 2 RNY units contain 2 x standard compressors. It sounds like you have poor capacity as only the inverter compressor is operational. Capacity increase will not occur unless some of the standard compressors begin to start, here lies the issue. If they are not loading up, then this can be a multitude of things, the best place to start is to take pressure readings on the operating RXY module, compare these to the DC voltage on the output side of the pressure transducers. If the transducers are reading lower than the actual operating pressure, then this will prevent loading of additional compressors as the system will not allow the pressure to drop too low for safety reasons. If the actual nmeasured pressure and the transducer readings match, then the system may indeed be low on refrigerant, or some of the modules may be set to not operate as they may be programmed not to. Compressors may be faulty etc. Call Daikins helpdesk and request the emergency operation settings and also check the set up the dip switches in the RNY modules, they should be set in order 2 & 3, module 1 being the RXY. Best of luck, these systems are **** to work on, over complicated and quite possibly the worst type of VRV Daikin made. The modern systems are far more understandable and easy to work on.Best of luck.