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