noisy daikin 600 sq cassette

[install monkey]

morning- got a vrv2 system, installed by our muppets 5 yr ago, 1 unit in canteen is noisy, start it up and after 30 mins the indoor fan buzzes its nuts off!
so i ordered a new motor,capacitor- fitted and again after 30 mins its noisy!- no outlets blocked, filters,coil clean.

swapped indoor pcb onto another unit-ran for 40 mins ok.
spoke with daikin technical and they suggested checking the power supply to the unit- checked and tested connections ok- as usual only time i can play with it is after 6pm for an hour and saturday mornings- no fault codes on the controller
http://www.mediafire.com/?oi4hv4yhen3e3l2

[Brian_UK]

Thinking sideways.... Is there anything lying or stuck in the drain tray that gets lifted by the fan suction at the higher speed and touches the fan blade?

[install monkey]

coils and drip tray are spotless, unit is level, screwed rod is secure,square- the fan cowl has no signs of rubbing, the fan blade has been inspected for hairline cracks all the glued joints secure and no play in the motor,blade runs fine, no sticker peeling off the motor, cable to the motor clipped as from factory- no issues with the unit since it was installed 5 yr ago,rubber mounts for the fan are fine- no cracks,

Thinking sideways.... Is there anything lying or stuck in the drain tray that gets lifted by the fan suction at the higher speed and touches the fan blade?

[Brian_UK]

^^ Dammit ^^, it does sound like electric harmonics though doesn't it?

[install monkey]

yep, changed the motor and cap, didnt solve it- put the indoor pcb onto another unit and ran it for 40 mins ok, the new motor wasnt noisy for the first 20 mins, the lead and the impellor havent been swapped but any issues of inbalance would cause vibrations as soon as the motor got upto speed.
by running in fan only proves it not lev issues, swing louvre, or internal lift pump, definatly motor issues, will have to check it and maybe swap pcb over and run it for longer.

also not power issues as 240 phase- e and phase -n 0v n- earth
and the other 63 indoors are ok, theres 22 indoors on that floor fed off 4 seperate ring mains- so the other 6 or 7 units on that ring are ok

^^ Dammit ^^, it does sound like electric harmonics though doesn't it?

[mikeref]

Ok, new motor and pcb and shared mains power with other units. Would it be possible to disconnect all plugins/Connections that are not necessary on pcb to allow ONLY the evap fan to run. Thinking there may be feedback from outdoor communications or trouble with outdoor board.

[install monkey]

mike its a vrv 1 outdoor unit 48 hp and 22 indoors and 22 bs (changeoverboxes) all on a common comms line, can only disconnect drain pump and louvre motor , all indoor units are close to 600sq high freq lights but its been in 5 yrs ​

Ok, new motor and pcb and shared mains power with other units. Would it be possible to disconnect all plugins/Connections that are not necessary on pcb to allow ONLY the evap fan to run. Thinking there may be feedback from outdoor communications or trouble with outdoor board.

[install monkey]

update- swapped all electrics- pcb, transformer,capacitor with another unit-ran it and it appears to be the motor
tested outputs off pcb on red ,yellow wire 140v ac black 0v
this is the same before/during noise
http://youtu.be/un3PcDt9CG0

[frank]

IM
I had one of these last 'SUMMER' (ha, what joke)

Have a close look at the fan impeller. The one I had showed signs of VERY tiny cracks in the 'Hub' that connects onto the motor shaft.

Everything looks normal, but when the fan starts to spin, the small cracks started to vibrate and emitted a sound like you are hearing. Just a thought. Try to swap an impeller with an adjacent unit and see if the noise moves with it.

[install monkey]

will try it on saturday frank when i return- 600sq cassettes are a pain in the arse as you have to remove cover,electrics to get the impellor out, as opposed to a 5 min rip it out, takes nearer 20 mins

[install monkey]

Update, couldnt get on site at weekend, amazingly the first warm day and customer is moaning about it.
Attended site and got permits. Inspect fan impellor and there was a crack in the plastic from the aluminium hub, approx 3 inch long, must have grown since i fitted the motor. Pinched an impellor of another 600sq unit and sat here monitering it
And drinking brews.
Also daikin fqs members havent replied to my video i sent them
Posted vid on u tube- no comments
Now all i have to do is source the part number for the impellor as climate ctr (not naming the branch) are so laid back theyre champion limbo dancers!!

[bigspee]

I had a similar issue last year with a noisy cassette 1200 mm, turned out it was the fan motor supply cable had managed to unfix itself and was catching the impellers.

[install monkey]

had it on old mitsi units where the inuslation tape around the back of the fan plug gets warm and started to unwind, causing a rustling noise but that was nothing like that daikin cassette- luckily replacement fan impellor is only 62 quid, so got it on order

I had a similar issue last year with a noisy cassette 1200 mm, turned out it was the fan motor supply cable had managed to unfix itself and was catching the impellers.