Daikin a/c

[aodhan]

CAN ANYONE JUST EXPLAIN STEP BY STEP THE ELECTRICAL SIDE OF HOW A DAIKIN COMFORT INVERTER MODEL NO: RZQS125c7v1b WORKS I.E WHAT EACH OF THE 4 PCB's DO, THE 2200uF CAPACITOR, WHAT VOLTAGE SHOULD BE AT DIFFERENT POINTS AC OR DC ETC.. THANK YOU FOR YOUR HELP!

[nike123]

Why are you shouting!
All is explained in service manual!

[aodhan]

What service manual are you looking at? The one i got from daikin deos not explain....

[nike123]

http://tinyurl.com/y9x5kgj
Chapter 7

[aodhan]

Still lost!

[Brian_UK]

Still lost!If it isn't in that Service Book then it isn't published.

[nike123]

Still lost!
If you present your problem than we could, maybe, help.

[croc1774]

i believe this was the question asked ?


Got call out to a daikin comfort inverter model no: Rzqs125c7v1b.... Found hole on 1 of capacitors on inverter pcb... Meggered out compressor, all ok... Replaced inverter board... Restarted unit... Compressor, outdoor fans not coming on and u2 fault code appears on controller... Tried disconnecting compressor and outdoor fans but fault code still keeps coming up on controller after about 10mins from switching on controller... What should i be checking out first when i go back to site... All help greatly appreciated!

read page 146 my friend from service manual, it will tell you what to check for.
if you have more than one unit on site try swapping boards over.
regards

[nike123]

Malfunction Decision Conditions:
When the capacitor above only has a voltage of 190 V or less.
Supposed Causes:


Power supply insufficient
Instantaneous failure
Defect of inverter PC board
Defect of outdoor control PC board
Main circuit wiring defect

...........................


C1 is capacitor on which you should measure 190V DC and above.
If you already changed inverter PCB and you have above 190V DC at C1 capacitor ALL THE TIME, than control PC board is faulty or main wiring is faulty..

[VRVIII]

CAN ANYONE JUST EXPLAIN STEP BY STEP THE ELECTRICAL SIDE OF HOW A DAIKIN COMFORT INVERTER MODEL NO: RZQS125c7v1b WORKS I.E WHAT EACH OF THE 4 PCB's DO, THE 2200uF CAPACITOR, WHAT VOLTAGE SHOULD BE AT DIFFERENT POINTS AC OR DC ETC.. THANK YOU FOR YOUR HELP!

Hi,

Why have you started 3 different threads to answer the same question :confused: I thought you Irish lads were supposed to be laid back and easy going :D

To fully understand the electronics on the latest digitally controlled inverters, you would probably need a degree in electronics :rolleyes: However most engineers are more than capable of following the appropriate service manual to allow diagnoses of a faulty component(s) :D
The manuals will point you in the right direction and list possible causes but you need to think outside the box.
IE. Possible cause for U2 error - insufficient voltage.
You measure 240vac at mains terminals but what is the voltage applied to inverter board when compressor tries to start (drawing current)? If you measure a drop in the voltage, this could be due to a bad L or N connection anywhere on mains supply, faulty noise filter or even a faulty pcb relay.

When replacing the PCB did you consider why the board had burnt out in the first place? If a PCB is replaced and the fan motor/compressor has an electrical fault, the new PCB can be damage.

Most manufactures now have the inverter & control pcb combined in one board reducing the fault finding process. If you use the search function you will find various threads relating to checking inverter circuits.


Looking at the wiring diagram for your unit you have 4 PCB’s:


A1P - This has both the main control board and inverter board combined
A2P - Service pcb with push buttons & LED’s, used to set field settings and to obtain information.
A3P - Single phase noise filter, normally used to clean mains supply.
A4P - Indoor / outdoor communication PCB


A1P inverter components:

K10R & K11R – Inverter control relays - when K10R closes, this will charge capacitors until around 280vdc is generated, K10R will then open & K11R will close (fans & compressor can then be started).
Z3F – Inverter ac noise filter
L1R (connected to A1P) – AC Reactor (used to improve the input power factor of the inverter power supply, reduce harmonics or suppress external surges)
V2R/V3R – Diode modules, converts ac to dc by chopping negative sign wave.
V1T – IGBT (insulated gate bipolar transistor), I think this is part of the rectifier circuit or possibly used to detect rotor position and communicate, when to switch the polarity of UVW inverter outputs depending on motor rotor position.
C1~C4 – Capacitors, used to smooth out ripples in dc supply.
M1F/M2F (fan motors) – These are also digitally controlled but they obtain a DC supply from the main inverter circuit (part of the inverter electronics is in built within the fan motor). Never disconnect or reconnect these motors when unit is operaring.
V1R – Power module (PAM - pulse amplitude modulation), this is where the transistors will switch in sequence to generate a variable frequency AC wave pattern.

[aodhan]

hello vrv111! done a quick check on unit today as had to go on another callout... 240v in and out of noise filter board so 240v onto main/inverter board...can hear a few clicking noises and then unit shows U2 fault... compressor and fans to not try to run... have a new board fitted... any ideas what to do next... thanks for your help... appreciated

[nike123]

hello vrv111! done a quick check on unit today as had to go on another callout... 240v in and out of noise filter board so 240v onto main/inverter board...can hear a few clicking noises and then unit shows U2 fault... compressor and fans to not try to run... have a new board fitted... any ideas what to do next... thanks for your help... appreciated
What voltage is on C1?

[aodhan]

hello nike123... is c1 the main capacitor(2200uF)

[VRVIII]

hello nike123... is c1 the main capacitor(2200uF)
No that is C4 capacitor.


hello vrv111! done a quick check on unit today as had to go on another callout... 240v in and out of noise filter board so 240v onto main/inverter board...can hear a few clicking noises and then unit shows U2 fault... compressor and fans to not try to run... have a new board fitted... any ideas what to do next... thanks for your help... appreciated


The clicking noises you hear will be K10R & K11R charging the capacitors then attempting to start, the unit will detect the U2 error and deenergise both relays. The unit will then wait 3 minutes and retry.
You will only have the DC voltage present when the relay is energised and it would be easier to check if you set your meter to record min/max voltage.

I would suggest you check:

Mains voltage L to N & N to Earth (240vac & 0vac)
Check AC voltage at LC NC terminals on inverter board (240vac)
When unit tries to start check for a volt drop at LC NC terminals on inverter board
When unit tries to start check DC voltage at C+C- on C4 capacitor (>220vdc)

Have you checked the capacitance of C4 capacitor? Did you remove the capacitor when replacing PCB? Did you reconnect it correctly? Most of these capacitors are polarity conscious.

Did you check you have resistance through L1R reactor? (This looks a bit like a transformer). Disconnect at X2A and check you have a resistance reading.

Did you meter out the inverter fan motors in accordance with service manual? (prior to replacing the PCB)

[troymedhurst]

Hi, not sure of model number of unit is similar to what i have worked on, but i too had u2 fault i replaced inverter board only for u2 to reappear after approx 3 mins, like yourself.
I found the problem to actually be a siezed fan motor , because it took a dc supply voltage off of the invter board.
I replaced fan motor and, luckily it had not damaged the new board, it fired up fine.
hope this helps

[aodhan]

hello vr111.... was back on site today and checked over unit... turned out had faulty reactor... took one off another unit and unit worked fine.... thanks for everyones help... greatly appreciated

[VRVIII]

hello vr111.... was back on site today and checked over unit... turned out had faulty reactor... took one off another unit and unit worked fine.... thanks for everyones help... greatly appreciated

Hi,

It's unusual for a reactor to fail, sounds like the inverter has suffered a serious dead short.
Thanks for the update :D

[DEVIL]

Now i got confused
What the heck is a reactor and in this case i suppose it's not a nuclear one :)

[VRVIII]

Now i got confused
What the heck is a reactor and in this case i suppose it's not a nuclear one :)


Hi Devil,
The reactor is normally used to smooth out power supply and reduce inverter harmonics being passed into mains supply. They can also be used to improve the input power factor of the inverter power supply or suppress external surges.
They look similar to a transformer see attached photo & inv wiring examples.
3294

3295

[DEVIL]

Hello VRVIII

Well didn't know that's the way they are called in English , i called them "ballast coils"

10q for the info

[VRVIII]

Hello VRVIII

Well didn't know that's the way they are called in English , i called them "ballast coils"

10q for the info

Hello Devil,

If you look at any (English) wiring diagram legend you will see, reactor is the term/description used :)