Hi everyone,

This is my first post on the site. Long time reader first time poster.
I'm impressed with the knowledge on here so I thought I would join.
Sorry if my first post is a headache

Ok, I have a Daikin 3.5kw cassette a/c (FFQ35C2VEB) that I have recently installed.
Upon commissioning I found the wall controller with no display.
Checked voltage at the control to be 3v DC ( it should be 16v DC)
Checked supply voltage to indoor to be 240v, so no under voltage issues.
I then spoke to Daikin tech who advised to change indoor PCB.

I returned to site and replaced the indoor PCB. The same problem occurred.
I then disconnected the controller so that the wires are just hanging there, and tested to find 16v DC
As soon as I re-connect the control it goes back to 3v DC and no display.
I even tried connecting a separate controller with a different cable in the roof to eliminate a shorted control wire. I got the same result, as soon as a control is connected it drops to 3v DC and no display.

I've got no idea what else to check and the Daikin tech seemed that way as well.

If anyone out there has any ideas i'd love to hear them.

Cheers, Keza