Daikin control problem

[wilko123]

Are there any Daikin VRV/Split Troubleshooting experts out there!!!!

Chiller biased myself so dont normally get involved but trying to help fellows out.

What they have is the following.....


1 x REYQ 12M7W1B LINKED TO

1 X REYQ 10M7W1B

13 X CASSETTE INDOORS AT HIGH LEVEL

7 X LOCAL CONTROLLERS

1 X DCS302 CENTRAL CONTROLLER

1 X DST301 SCHEDULE TIMER

THE WHOLE SYSTEM SHUTS DOWN AT INTERMITTENT TIMES ON U4 FAULT CODE
:rolleyes:
THEY FEEL THE CENTRAL CONTROLLER IS FIGHTING THE LOCAL CONTROL BUT CANT BE SURE.......???

WHEN THEY RESET 1 LOCAL CONTROLLER TO CLEAR FAULT CODES THE WHOLE SYSTEM SHUTS DOWN...

SOMETIMES LASTS 4 HOUR OR 4 DAYS NO RHYME OR REASON BUT I NEED TO GET IT SORTED ASAP

Any one out there who can offer support/advice?

MANY THANKS WILKO

[wozza]

I dont think it would be the centralised, but you could always try disconnecting it, run it on the local controllers for a week or so and set up the scheduales on the local remotes.
At least that would illiminate the centralised.
Is the interconnecting cable near any mains? Is the interconnecting cable a 2 core with no earthing at either end?
How old is the system? Possibilty od break down of the interconnecting cable or pcb failure.

[frank]

Whenever you have an intermitant fault, you have to consider if it is caused by interferance to the data transmission on the F1 F2 wiring.

If a pcb goes down then it does not recover.

If the system worked in the past but now plays up - has someone installed new cabling near too your data cable??

Look at the whole picture - not just the fault code.

[Dr Death]

This might help?

2.46 “U4” Malfunction of Transmission between Indoor Units

Remote
Controller
Display

U4

Applicable
Models

All model of indoor unit
REYQ8~48M

Method of
Malfunction
Detection

Microcomputer checks if transmission between indoor and outdoor units is normal.

Malfunction
Decision
Conditions

When transmission is not carried out normally for a certain amount of time

Supposed
Causes

�� Indoor to outdoor,outdoor to outdoor transmission wiring F1, F2 disconnection, short circuit
or wrong wiring

�� Outdoor unit power supply is OFF

�� System address doesn’t match

�� Defect of indoor unit PC board
�� Defect of outdoor unit PC board

[VRVIII]

Sound like you could have a bad connection somewhere on the F1F2 comms or breakage in one of f1f2 cables. Rats and mice also love to chew on the cables I’ve had a couple of times.

I have also had something similar due to a bad mains power connection within the indoor spur.

It could also be interference but this doubtful if the system has been operating with no previous comms problems.

I would suggest checking dc voltage at various points along the F1F2 comms line and see if you find a voltage drop anywhere the voltage should be a constant 15~16vdc when the system is initialised.
Then check F1F2 connections and local BS box/indoor islator connections.

[wilko123]

Thanks for your input everyone, i will do some more investigating!!

[Roadrunning123]

Hey Wilco ,
It's a communication fault between the two controls, make sure that the dip switches on the back of the controllers are set for two controls.
You can also check directly with daikin, they have a site running with all the pdf' s your brain can stand !
Good luck ;)