Vrvii

[icecube51]

Hey Guys,

have a client whit 12 VRVII units on the same roof, and sinds the start-up in 2008 whe had to replace 3 invertercompressors and 4 inverter PCB boards. whe checkt and monitord the current (3x 380V) an frequency and it looks OK.
anybody have a simmilar problem on these units plaese share the outcome or solution found.

many thanks, Ice

[El Padre]

Hi Icecube,

Did you see how much oil was in the failed compressors? If so did you test the oil for acidity? Are the refnet joints in the correct plane? Does the system run under low load conditions regularly?

Just a few situations that I have come across, I have got sites however with loads of G, H and J series systems that have never had a problem.

What are the chances that the install team purged Nitrogen through the pipework when they fitted the system?

Hopefully VRV III might get back from the pub soon!

Cheers

[VRVIII]

Hey Guys,

have a client whit 12 VRVII units on the same roof, and sinds the start-up in 2008 whe had to replace 3 invertercompressors and 4 inverter PCB boards. whe checkt and monitord the current (3x 380V) an frequency and it looks OK.
anybody have a simmilar problem on these units plaese share the outcome or solution found.

many thanks, Ice

Hi Icecube,

Are these systems REYQ 3 pipe heat recovery or RXYQ 2 pipe heat pumps? Did the inverter boards fail due to failure of compressor motor windings?
Have you checked/monitored the mains neutral for a fault? (possible loose connection at DB).

I would first check for any installation issues.
i.e.



Are systems within pipe limitations?

Outdoor to furthest indoor 165m actual max or 190m equivalent max
First refnet joint to furthest indoor 40m max


Have correct pipe sizes been installed?

When outdoor to furthest indoor exceeds 90m equivalent (about 70ish actual) the pipe work must be upsized from outdoor to first refenet (which pipe requires upsizing depends on model.


Was OFN used during pipe work installation?

This will contaminate oil, cause blockage of oil ways and can cause valves to stick.


Could any of the indoors have recirculation of discharge air? Example, cassette installed too close to walls.

This can cause the system to continually change mode when indoor is operated in auto.
After replacing compressor I would check and monitor the following:
1/ Check calibration of thermistors



2/ Check calibration of pressure tansducers

To check this you will need to measure the dc voltage across the white and black cable cores at the press transducer PCB connection (red & blue 5 pin plug connected to PCB). You can then cross reference the dc voltage with table in service manual and check with actual press measured on your manifold gauges.
IE. 2vdc = just under 2MPa (20bar)

Plug red & black wires = Constant 5vdc supply to transducer
Plug white & black wires = Variable 0~5vdc feed back to PCB
3/ Verify correct operation of expansion valve motors (in both heating & cooling mode.


4/ Verify correct operation of revering valves (in both heating & cooling mode)

Valve energised = heat exchanger operates as evap.
Valve de-energised = heat exchanger operates as condenser
You may find that bottom heat exchanger (smaller reversing valve) is operating as a condenser depending on operating conditions
5/ Verify correct operation of solenoid valves

Check there is no bypass across Y7S solenoid valve (looking into unit this is the right hand valve of the 2 with large green coils). This valve will be closed when outdoor is operation in heating or heat recovery.
The connected vertical pipe is LP and the horizontal pipe is HP, again this can be checked for a temp increase across the valve.
Also check Y6S liquid line solenoid is energised, this must be open when operating in heating or heat recovery (small valve in left hand bottom of unit with the coil mounted on horizontal valve stem).
6/ Check crank case heaters

[icecube51]

thnx VRVIII, i think in each of youre assumed probebly cause i can find a fault.
the install was not done by us, but now because of the never ending trouble and the luck of finding someone ho is able to do something about it, they hold one an ty to repair where possible and hope in coöperation whit Daikin to get al the troubles solved.
i am happy to get a serius second opinion because they are playing ping-pong over here on who is going to pay for what.

thnx, Ice

[DEVIL]

well VRVIII did a good job making a check list for you what i want to add is hight difference (it's pretty important).

But..... judging that there went so many inverters down, and including the PCB's i tend to belive it's an electrical problem , despite that sometimes wen an inverter comp is going down it might take the inverter PCB with it.

you tested the electrical properties but you didn't log them, so it might be ok when you test but 1 hour, 10 hours, 2 days after it might get bad and then back ok, or you might have grounding problems.

And don't forget, VRV II has a oil equalization tube, is it fitted properly ?

[icecube51]

last time that there was a current/ voltage problem was about a mond ago. when that happens, the generator thakes over. i am going to find out when there was a change of powersupplier, so if the dates are closely together whe can link one another.

Thnx, Ice

[wigs]

I too have had this problem with one site that has VRVII systems, we have changed many compressors always the M1 inverter compressor my suspicions are that the installer cut corners by not purging nitrogen during the installation. And when we contacted Daikin they informed us we needed to change the inverter PCB as well as the compressor however we have tested the inverter drive and have found nothing wrong so far.

4 VRVII systems, 4 replaced inverter compressors, no Inverter PCBs required.

[DEVIL]

I have to admit that i am not proud of the way the inverter PCB protects itself and that's way in Romania some supplier reduce the warranty because they say we have electrical power problems, but i have to admit i had in one place 3 VRV II and one VRV III , and they had 340 V instead 380 V, and i informed the client that there will be problems, but you know how they say we have to make it work and we are going to handle this problem as soon as possible.
So 8-9 months later went on the site (in the middle of winter and they used it for heating sorce) because the system didn't work no more, so discovered one of the standard compressor suffered for the problem described before , so replaced the compressor, of course the client payed it all (warranty was void).
Now hers way the client didn't handled the electrical problem before, here in Romania and you got to love this , wen you are needing more power, all the improvement are made at your expense, and then all the new parts (wires and so one) are they're property.

So the client had to pay for 70 m of power cable and some protections so the electrical company can supply the necessarily power around 47000 Euro , and then all the materials was owned by the power company.

but the conclusion that amazed me was that in this harsh conditions no inverter or any PCB was harmed