Daikin vrv seriously need help

[ktm]

Need some serious help with an old Daikin vrv sytem. It's heat recover r22.

Models of equipment:


Function unit: Br3kjv1
Rny10ky1r by 2
Rxy10ky1r

With 13 indoor units attached.

The problem we are having is that the system won't load up on heating. System will run fine in cooling. Spoke to Daikin and replaced low pressure transducer. Fit service checker to system to check out door expansion valves were operation correctly all seem fine.

System has bein pressure tested and evacuated down to 350 microns so I know there nothing wrong with charge. Inverter unit starts and brings on the other too but they only run for 5 mins before they unload. Coil temps only get up to 35 to 40 c.

I have sent the service checker info to the Daikin europe head office and am waiting to hear back just taught someone else may have come across this prob.

I was only on site to fit service checker another lad has bein there over a week now checking everything so if there is more info needed I can get it quick enough.

Thanks in advance any new ideas would b great.

[marc5180]

I know you say you vacced down to 350 microns so the vac is good but is the charge correct?

I dont work on Daikin much so i may be wrong but after looking at the piping diagrams the obvious thing for me to check would be that the discharge solonoid is open and the 4 way rv arent stuck.

What pressures are you getting? i.e is the discharge ramping up to target discharge pressure 25-28bar?

[ktm]

Yes the charge is perfect. 64kg long pipe runs.

The head pressure was up at 18 bar when I was on site. The service checker shows all valves are open correctly but I did question if there could b a mechanical problem with a valve and no show up on the service checker. I will ask the guy in site to check and post results. Thanks for the quick response.

[marc5180]

Sorry i've just re-read my post 18bar seems normal doesnt it because it's on R22 not R410a

[ktm]

Yea that's cool taught it was just me

[VRVIII]

Need some serious help with an old Daikin vrv sytem. It's heat recover r22.

Models of equipment:


Function unit: Br3kjv1
Rny10ky1r by 2
Rxy10ky1r

With 13 indoor units attached.

The problem we are having is that the system won't load up on heating. System will run fine in cooling. Spoke to Daikin and replaced low pressure transducer. Fit service checker to system to check out door expansion valves were operation correctly all seem fine.

System has bein pressure tested and evacuated down to 350 microns so I know there nothing wrong with charge. Inverter unit starts and brings on the other too but they only run for 5 mins before they unload. Coil temps only get up to 35 to 40 c.

I have sent the service checker info to the Daikin europe head office and am waiting to hear back just taught someone else may have come across this prob.

I was only on site to fit service checker another lad has bein there over a week now checking everything so if there is more info needed I can get it quick enough.

Thanks in advance any new ideas would b great.

Hi KTM,

Hope you’ve got the bike to match the name
Are you from the North or South? I’ll hazard a guess at the south.

The R22 VRV Plus units are very difficult to understand with a service checker, it will only show you what the pcb is out putting and receiving from the sensors. You would need to judge if solenoid valves, reversing valves and expansion valves are operating correctly based on the thermistor readings.
i.e. If the reversing valve is off (de-energised) the heat exchanger should be operating as a condenser & the heat exchanger header sensor should be similar to Tc (sat condensing temp)
It will not automatically highlight a problem to you.

Connecting the service checker directly into the function box pcb (not F1F2 terminals) will give a much faster update time.

[install monkey]

filters clean on indoors? grilles havent been blocked off to reduce airflow?
check mode 41 for coil,return air,controller temp values.
any bms interface or fault codes?

[gqm001]

On the newer units I have had a lot of problems with the outdoor thermistors losing their values but not showing as a fault, because of this the unit does not operate as epected.
The other problem is installation of fresh air supply ducting being installed to close to the rear of a ducted unit when the ceiling void is used as plenum, sometimes the units will struggle to overcome the cold supply air. in this case if the return air sensor is in the indoor unit it will show that the system is working hard but without the expected performance.
I expect that these are just things that we all would normally check but its always worth hereing other peoples views.

[ktm]

Thanks for all the responses. Yea I was thinking we should check all the valves manually and not just listen to the service checker. The system never showed any fault. There is no BMs sytem only I touch. The only sensor that was reading off was one of the oil sensors which was replaced. I did think that fresh air on was too cold so the ahu were all turned off. This made no change to the system. I think I will try get back to site asap and go throughall the valves one by one.

I do think it is a valve that is mechanically not operating correctly although it may be showing the correct pulses on service checker and not generating the fault. It's difficult to know were to start,
Especially when u not working on the site.

VRVIII I didn't know they made bikes
Your correct on both accounts I'm from the south and I have 2 ktm bikes.

Il keep u posted on what we find as soon as I can get back to site. Maybe the other engineer will have some more ideas 2m.

Thanks again

[VRVIII]

System will run fine in cooling. Spoke to Daikin and replaced low pressure transducer.

I would suggest you first check the calibration of the discharge pressure transducer (not the LP transducer) this has the main influence over compressor capacity in heating mode.

It’s easier to check the calibration of all sensors before you start,
Connect service checker
Switch off all indoors at controllers and allow outdoor to stop
Wait 30 min to allow pressures and pipe temps to equalise
View checker to verify sensors are around the same value (discharge & oil pipe temps may be higher)


Turn all indoors on in heating mode, when the system has been operating for 20~30min check the following at function unit and each module
Ø Mode of operation – number of operating compressors
Ø Head pressure – discharge temp – discharge superheat
Ø Liquid line pressure
Ø Suction pressure – suction temp – suction superheat

Average indoor liquid, suction, air on & air off temps

[ktm]

Tanks for the ideas. I will try check these things when I get back to site next week. Thanks VRV III for getting back so soon great to have someone with a few new ideas. Il keep u posted.

[1torr]

Hi. Did you get to the bottom of this problem?