BOTH LED ARROWS SHOULD BE FLASHING here. The data is bi directional on the same wire. My understanding is that one LED means positive half cycle data transmitted in one direction and the other LED means negative half cycle data pulses in the other direction. ( indoor unit to outdoor unit or visa versa) See "Refco data flow test module" video at 1.08 minute mark..
They don't specify it that well, I get better results using a CRO. Most outdoor units start the comms process, This unit it was tested on was fully functional and from a well known brand. Each indoor/outdoor has a transmission and receive circuit , yet this is what the tester was showing at the time.
Why bother setting up an oscilloscope to do this and the risk that this entails? The usual way to do it is a lot faster and easier i.e as per the fujitsu service instructions. Take the data wire off at the interconnect terminal with an insulated screwdriver and measure the voltage on the wire and the terminal. The dead one is the dead one! Surprise!! (the voltage is unusual , it's not 240 volts, don't worry about that) For any reader's who don't know what I mean: If you are at the outdoor unit and the wire is live and the terminal isn't, then the outdoor unit is not transmitting data. This is a common fault as most faults kill the high voltage DC supply to the control board as it is derived from the filter board, IPM rectifier, ACTPM D.C bus regulator, the capacitor board and back to the IPM before it energises the control board (In the models with 4 boards in the outdoor unit.) PS Readers should not get too excited about using a CRO on these inverters unless you are very experienced at repairing variable frequency drives. Never put a CRO's earth lead on the 0 volt rail of the 340 volt DC supply. The 0 volt rail, as it's called on the diagrams, is really at minus 170 volts and you will blow the bridge rectifier on the IPM. Any AC supply that you full wave rectify will be at plus and minus DC levels relative to the common ( the neutral in this case)
Sure, I can get a statical reading of around 45vdc based on the manufacturer info and that's means the comms is ok buts that's only generated at the outdoor. I was having a look at what this tool does and that is the way it is connected. The unit was not running and the indoor does not communicate to the outdoor fully until a mode is called for other than fan only.
Can this test directly on the compressor?because I have a Fujitsu mini split inverter keep having faulty PCB board,some say because maybe the compressor has kind of sorting or something but when replaced the PCB the compressor running very smooth and very cold
The tester is designed to check the power transistor switching on the inverter pcb. The compressor test alone would be resistance based. Testing any insulation faults is a must on the compressor as the IGBT will fail quickly on compressir earth shorts. Find your manufacturer testing instructions for the compressor
You can use it, but in terms of necessary, not really. Manufacturers have their flow charts and readings for tests like this in the service manuals. As I mentioned in the video, I did not find it conclusive.
Hello Dennis, I recently bought this device and when I try to check the data flow between idu and odu both data lights aren't flashing but they are just turned on. I've seen many videos but I still can't solve the problem. Any ideas on what's going on with my device?
Hi, thanks for your comment, I found my test a bit inconclusive based on what real info I know about the brand of unit I was looking at. Not all brands are the same and comms styles vary. Your looking at an analogue signal which can be detected both ac and dc on some multimeters It's a handy thing, too, since if you take a 2 wire wall controller, the signal is both a power supply to make it light up and function, and an AD signal to the indoor pcb. This is why many brand manufacturers provide their own comms tools with real-time read data. This tool is just pinging signals in voltages. I suggest checking with the brand manufacturer of the unit your servicing as I found this tool not compatible on the same maker's brand across other commercial models using the same interconnect.wiring between indoor and outdoor.
Good night. Vx could provide the schematic of this test. Or sell. And the schematic of this inverter test that vx uses to diagnose errors both ipm, serial, and so on. This device in this box. Thanks for the Daikin Service Manual.
Hello, my name is Claudius and I'm from Romania and I can tell you if this tester can help me to find out the cause of the problem if an air does not start and gives me an error. I have a problem with an air of NEO brand INVERTER 12000 btu, you start on cold starts the fan and after 5 seconds without having to start the compressor or outdoor fan shows me F1. Temperature sensors are good, 5 kohm inner and out of 5 and 50 kohm compressor outlet.
This tester is a simple diagnostic for commications from indoor to outdoor, you will have to check with the manufacturer on what the alpha/numeric fault code F1 means. If your getting a fault code, it must have some functional micro processor at the indoor unit.
With ac or dc there are no positive or negative voltages , meters read negative voltages when they read opposing current flow from their designated polarity. If i reverse this tester, it will read opposite. I found this device not conclusive to what I do know about the unit I was testing.
