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Latte
02-03-2006, 10:31 PM
Hi Guys,

Got called out last week to a large office block with a Daikin VRV System (RSXY8HJY1) showing L9 Fault (Compressor stall).

Checked outdoor inverter board, led 1 flashing, next 4 all on confirming. Switch off and reset try again same fault. Check output of inverter board between u,v & w
Only getting anything from 30 to 0 volts between points. not even close to being ballanced. Condemned board. Checked compressor windings 2 ohms between points and no sign of earth leakage.Even rang Daikin following day to check and they confirmed.

Now gone back today and fitted new inverter board, still get L9. Check outputs of board 200v between points when pot disconnected. Phoned Daikin and advised compressor has seized and high amps caused inverter board to fry.

NOW !!! my question. How on earth do you diagnose this first visit. Unless the board is OK you can see the pot is knackered but if the board u/s you cant check apart from the usual as above.

What do you guys do. Personally the only way i can see is if you get a failure of one (board or pot) then just replace both. It just concerns me that it will be expensive to do each time and it's not strickly professional to replace more parts than may actually be needed

Any Advice

Regards


Fatboy

rbartlett
02-03-2006, 10:54 PM
of course you did everything right -even hopefully explaining to the customer that the compressor may still be faulty when you quoted them.

However in all honesty I would usually quote for both and if feeling generous say if the compressor runs then you will only be billed xz %

the real worry is that if you do change just the bits and switch the unit on if it Fries them again you will have trouble with warranty

However as inverters are now pretty much the norm it's going to be expensive out there in the next 5-10 years or so..

cheers

richard

Tycho
02-03-2006, 11:21 PM
Don't know how these kinda units are connected.

But how about bypassing the inverter board and run 220V (if thats what you have) straight to the compressor, so you can check the amps and see if the compressor turns at all?

lin
03-03-2006, 12:34 AM
Don't know how these kinda units are connected.

But how about bypassing the inverter board and run 220V (if thats what you have) straight to the compressor, so you can check the amps and see if the compressor turns at all?

Don't do so !
the compressor maybe never rating at 220V/50HZ. (the voltage supplied by inverter at 50HZ isn't 220V, it's determinated by V/F formula)

frank
03-03-2006, 04:57 PM
How on earth do you diagnose this first visit.

Use a Daikin Inverter Test Kit. This will tell you if the fault is with the board or the PCB.

Available from Space Airconditioning :)

rbartlett
03-03-2006, 05:11 PM
Use a Daikin Inverter Test Kit. This will tell you if the fault is with the board or the PCB.

Available from Space Airconditioning :)


will it tell you if the compressor is seized??

or is it a case of if the electronics is okay then the compressor must be faulty??

cheers

richard

frank
03-03-2006, 05:15 PM
You connect the kit and a series of lights will indicate which side the fault is on, either PCB side or Compressor. Which ever side is faulty needs to be replaced. Doesn't really matter if the comp is seized or not - if the kit says it's faulty then it has to be replaced.

Mickvee
03-03-2006, 08:17 PM
Could you use a small motor of similar size connected to the inverter board to test it :confused:

Andy
03-03-2006, 08:30 PM
Hi:)
from memory the compressors are DC, the inverter boards don't need to then convert the D/C square wave back to A/C, cheaper and with higher starting torques.

Frank correct me if I am wrong as I don't work on A/C (unless on Industrial production areas, which is usually Ammonia or R22/R404a)

Kind Regards. Andy:)

bobjob
03-03-2006, 09:36 PM
Re: inverter systems

Daikin can supply a device which will takes the the place of the compressor so that the inverter PCB can be checked.
The three wires from the compressor are removed and fitted onto the daikin box (device)
and then by switching on the inverter compressor you are able to see the series of leds on the box light up and pulse with the frequence supplied from the Inverter board.
It is a good tool and i have used it on other makes of inverter compressors.
a word of warning though is that the dropping resistors get very warm so it can not be left on for over 5minutes

Bob

frank
04-03-2006, 03:03 PM
Hi:)
from memory the compressors are DC, the inverter boards don't need to then convert the D/C square wave back to A/C, cheaper and with higher starting torques.

Frank correct me if I am wrong as I don't work on A/C (unless on Industrial production areas, which is usually Ammonia or R22/R404a)

Kind Regards. Andy:)
The older systems were all AC inverter compressors but every manufacturer now seems to be going for DC reluctance compressors. As you say, more torque available at lower speeds.

aeb200
04-03-2006, 03:15 PM
[QUOTE=frank]Use a Daikin Inverter Test Kit. This will tell you if the fault is with the board or the PCB.

Frank -will this test kit work on other manufacturers units like mitsubishi, MHI and sanyo inverters? - does it just check inverter output

Latte
06-03-2006, 07:50 PM
Hi Guys,

I am going back to fit a new pot tommorow, now having never done one before this is what i intend to do and i think its one of those cases where you don't go exactly by the book !!!.

Now i intend to shut off the valves at the VRV unit, reclaim the gas inside it (I assume there is a port there somewhere) Change pot, pressure test under staning pressure in case valves bypassing, vac out and recharge weight taken out.

Now, i am sure the correct BY THE BOOK !!! procedure would be reclaim complete system so you can do a strength test but this will take days to reclaim a large office block.


Now, another point. Space doesnt seem to be a problem inside these units so why don't the manufactures make them like pack systems with service ports on the pots so you don't have to reclaim the whole CU. Splits only hold a couple of KG so it doesn't take long to reclaim but i would think a VRV holds 6-7 kg min.

Any comments

Regards

Fatboy

frank
07-03-2006, 01:40 PM
Any comments

Hi Raymond

Thats exactly how we would do it.

One thing to check though before you fit the new pot is to measure the amount of oil in the old pot.

The factory charge for the RSXY8 was 1.5 lt of Suniso4GS in the inverter comp and 1.4 lt for the fixed speed comp. If you have around a ltr then just fit the comp but if you have considerably less than this it means that most of the oil is floating around the circuit and will be returned to the new compressor during the next oil recovery cycle. This could result in an overcharge of oil and may cause damage to your new compressor.

If you get more than 1.5 lt out of the old comp then you need to add more oil (measured qty - 1.5).

Latte
10-03-2006, 10:13 PM
Hi Guys,

Got the compressor fitted OK. Managed to pull 2 dumpy reclaim bottle out of the rooftop unit. I got one of them back in the system ok but the pressure too high to get the second back in.

I assume i need to get the second compressor running as well to drop the suction enough. How can you do this. Inverter compressor running OK as is the fan
Any ideas

Regards

Fatboy

frank
12-03-2006, 10:13 PM
Put the system into Test mode

Latte
15-03-2006, 12:40 PM
Hi Guys,

Just an update, Spoken to Daikin Technical today
Inverter analysers are available from the stores at 79 list price. According to Daikin, these do work on all inverter systems (Mitsi, Tosh etc) and very easy to use.
If it saves one misdiagnosis then it's paid for itself.

Will have to try and get out company to buy one, getting too many compressors and boards failing

Regards

Fatboy

star882
01-04-2006, 06:50 PM
Disable the evaporator fan to put the charge back in.
But you may want to actually measure the charge. Perhaps it was overcharged causing the compressor to fail.

paul_h
10-07-2007, 04:05 PM
I work with fuji inverters, and to test the PCB you only need to do two things.
1 verify the board works, with most things unplugged, the power relay should come on, TX valve/s operate, comms signal good.
2. Check the diodes on the IPM with your multimeter on diode setting, ie. the power to the module that drives the compressor, and the three outputs. It should be a given voltage one way, and open circuit the other.

I'm surprised that daikin are any more complicated. I know fuji isn't alone, their IPM and compressor was made by mitsubishi afterall

superswill
10-07-2007, 06:08 PM
the daikin part number is 1225477 and they call it a power transisto checker,i use mine on every make of kit and for about the money has never let me down yet and saved alot of second calls

p_p
10-07-2007, 07:56 PM
Hi All

Get yourselves on the LG course, the inverter testers are free and the trainings very good too.

Regards PP

kerrcell
10-07-2007, 08:19 PM
Hi Have read your querry.I do work on another brand and am faced frequently with this problem.Honestly my boss never sent anyone for a technical course.I am qualifier in HVAC/R and also in electronics.But these won't help.Another problem is the cost of an outdoor unit's inverter card.From my side i don't find an inverter worth installing for these problems.Some of them are installed just for 4 years.The shout is that they are economical.Honestly to say,in 4/5 years time an electronic card that costs one third of the price of the whole a/c unit does not cater for electrical savings.

superswill
10-07-2007, 11:47 PM
Hi Have read your querry.I do work on another brand and am faced frequently with this problem.Honestly my boss never sent anyone for a technical course.I am qualifier in HVAC/R and also in electronics.But these won't help.Another problem is the cost of an outdoor unit's inverter card.From my side i don't find an inverter worth installing for these problems.Some of them are installed just for 4 years.The shout is that they are economical.Honestly to say,in 4/5 years time an electronic card that costs one third of the price of the whole a/c unit does not cater for electrical savings.


with most manufacturers doing up to five years parts warranty ive never really found this a problem,ok so as a service engineer you rely on the quality and competence
of the install you attend but it's that what we are paid for? to make good? over to you guys

stuartwking
11-07-2007, 12:14 AM
I have found that using the inverter tester supplied from Daikin can show all ok, but once put under load, i e comp connected to it the IPM can still not fire correctly.