Daikin vrv 11 !!!

[Darrenp]

Hi fellas ,,, been called to a site , vrv tripping mcb breaker , this has happened a couple of times over the year , random really , have checked comps, major components , all seem ok , when I get to site system runs ok , doesn't trip whilst I'm on site !!!

What can it be ,, anyone !!!

[Darrenp]

That's a daikin vrv 2 ... Not eleven ,, ha

[bigspee]

Faulty MCB? Lol stab in the dark

[redroge]

Check outdoor isolator for moisture.

[markdenford]

Hi fellas ,,, been called to a site , vrv tripping mcb breaker , this has happened a couple of times over the year , random really , have checked comps, major components , all seem ok , when I get to site system runs ok , doesn't trip whilst I'm on site !!!

What can it be ,, anyone !!!

I second redroge reply I've had the very same issue and found moisture in the isolator, fitted new one problem solved .

[install monkey]

have u meggered the compressors,cable rubbed on metalwork?

[frank]

have u meggered the compressors,cable rubbed on metalwork?
Speaking of cable rubbing on metalwork....

Here's a couple of photo's that caused me grief. It's off a Daikin Skyair pair install. Fault code was an intermittent U4 - indoor/outdoor comms problem.

Third visit to site I investigated further and found the armored cable interconnect wire rubbed through. It was at the point where the cable ran into the outdoor unit and passed across the compressor holding bolt.
http://i116.photobucket.com/albums/o38/frankyboy_01/DSCN0535.jpg
http://i116.photobucket.com/albums/o38/frankyboy_01/DSCN0536.jpg

[Darrenp]

Sorted , pretty much found that inverter pcb and inverter contractor buggered , checked comp withe megger seemed ok , but getting comp just to be safe ,, tell me why do these Japanese make it so bloody hard to get to the pcbs , getting to the noise filter board was a nightmare !!

[frank]

If it's sorted, and the compressor checked out OK with the megger, why are you putting the customer to the expense of changing the compressor?

[Darrenp]

Because all checks pointed towards the comp melting the inverter contactor , even tho the comp seemed electrically sound I.e windings ok , could of locked out/seized. ..

[Darrenp]

Not taking the chance of getting a pcb for the comp to blow it up , thus putting the customer to more expense frank

[frank]

Inverter compressors don't have contactors??

[Darrenp]

Yes it does , behind the power box , next to noise filter board , magnetic contact relay if you like , acts the same , a1 a2 feeds the inverter pcb ..

[Darrenp]

Ok let's say its for the whole inverter circuit then !!!

[redroge]

If the compressor Is,nt down to earth it should have tripped on L8 or L9, I would also check the compressor four wire plug as I,ve had a couple where the reds burn,t

[Darrenp]

Just an update , done the job today , as suspected the inverter comp was seized , as when I got there I put the dol comp wires on inverter , pushed the contactor in and wallop seized comp took the breaker out , so lucky I did eh , as if I only got pcb and contactor , probably would of taken new board of the scene again , unit running like a dream now

[install monkey]

you need to be careful when adding 3ph d.o.l to an inverter compressor as the winding resistance is only around 1.1ohm per winding as opposed to around 2-3 ohms on a d.o.l compressor- only recommended for a short time (advised of this off climate technical)

[Darrenp]

Yes I know , just a quick push of contactor to make sure the inverter comp was buggered , practically 1second , took the breaker out , stalled inverter comp

[frank]

Where do they teach you this on the Daikin VRV course?

Words fail me...

[Tayters]

A way of testing an inverter compressor which i've often wondered about but never tried it myself.

I've believe the windings can be a lower resistance and the compressor motor is designed to start slow then build up. When you connect it to a 3 phase supply then you will get LRA which according to Andylogic may cause the breaker (depending on size and motor rating type) to trip even though the compressor isn't seized.

Out of interest has anyone ever done this and proved the motor to run?

Cheers,
Andy.

[install monkey]

hitatchi vrf recommend it to test the inv compressor but only recommend for a few seconds- as the inv comp windings is only around 1 ohm as opposed to 3 ohm on a standard dol comp

A way of testing an inverter compressor which i've often wondered about but never tried it myself.

I've believe the windings can be a lower resistance and the compressor motor is designed to start slow then build up. When you connect it to a 3 phase supply then you will get LRA which according to Andylogic may cause the breaker (depending on size and motor rating type) to trip even though the compressor isn't seized.

Out of interest has anyone ever done this and proved the motor to run?

Cheers,
Andy.

[Darrenp]

It's all good people , stop panicking , system running , 18 bedrooms now heating , customer happy , engineer happy , inverter pcb was blown , pointing to comp , all other components checked , all sound , apart from inverter circuit contactor , so pointing towards the comp blowing the pcb and melting the contactor , job done

[install monkey]

did u do an acid test and replace the oil from the other compressors??:D

[Darrenp]

Did acid test yes , all ok , no didn't replace oil in other comps

[install monkey]

did you update the f gas sheet for removal,pressure test and recharging?- valves driven open for degassing,pressure test,vaccing?:p

[Darrenp]

Yep , f gas log filled in, setting 21 on pcb for reclaiming , pressure testing & charging , all done install monkey , anything else ?

[Darrenp]

Oh and vaccing , which pulled to 1 torr and held

[VRVIII]

Just an update , done the job today , as suspected the inverter comp was seized , as when I got there I put the dol comp wires on inverter , pushed the contactor in and wallop seized comp took the breaker out , so lucky I did eh , as if I only got pcb and contactor , probably would of taken new board of the scene again , unit running like a dream now

Never connect 3ph directly to the inverter compressor(s) fitted to VRV II, III or IV, these are digitally controlled. Connecting 3ph directly will instantly trip the circuit breaker if the compressor is good or bad.

[Darrenp]

Well I was given this method to do and told its a sure way of testing the inverter !!!

[Darrenp]

Daikin technical

[VRVIII]

Well I was given this method to do and told its a sure way of testing the inverter !!!

Yes this could be used on VRV G/H/K series (>10 years old), inverter technology has come a long way since then!!!