Comms Problem

[aza]

Hi Guys,

2 Fujitsu ceiling cassettes, 2 outdoor units.

Problem..... 2 cassettes, 1 controller, Master- Slave situation.

Master works fine slave doesn't comunicate with outdoor unit.
As far as i am aware the controller is wired correctly, wires 1,2,3 in master and 2,3 in slave. Units identified as 0 in master and 1 in slave.

2 outdoor units identical and have swapped everything but no joy so problem must be in ceiling cassette.

Any ideas ??????

[frank]

The cassettes don't communicate with the outdoor units via the controller - they communicate via the indoor/outdoor wiring.

What's the problem - what does it not do???

[aza]

Sorry Frank had a long weekend.

The problem is that when you switch the system on both indoor units switch on but only 1 outdoor works, so the slave unit not communicating with its own outdoor unit.

[superswill]

or could it be a fault on the outdoor unit? a safty maybe
? try running the "slave" unit with the controller as a one on one unit,are you getting any fault codes?

[Jase]

Hi can you use a volt meter and fault finding techniques to source your problem. also make sure you have programmed the controller for 2 units...!!!

Regards Jase

[digi-finger]

Check the link wire, does it have a isolator? How quickly does the error show after isolation? Problem may be caused by user. All to often the case!

[aza]

Hi Guys,
Thanks for your thoughts but hopefully I sorted it today, after swapping nearly every pcb and parts on the units.

What was causing the problem was that a tank pump was fitted to the side of the slave unit and when it kicked in to pump the water away it stopped the outdoor unit working?? Haven't got a clue why but gave the pump its own power source instead of connecting to the cassette and now everthing works fine..........fingers crossed

[superswill]

Hi Guys,
Thanks for your thoughts but hopefully I sorted it today, after swapping nearly every pcb and parts on the units.

What was causing the problem was that a tank pump was fitted to the side of the slave unit and when it kicked in to pump the water away it stopped the outdoor unit working?? Haven't got a clue why but gave the pump its own power source instead of connecting to the cassette and now everthing works fine..........fingers crossed

was the pump high level wired thought the comms cable?

[fazzamouse]

was the pump high level wired thought the comms cable?
you should always give the tank pump its own power source.

[superswill]

you should always give the tank pump its own power source.


sorry my post was vage,by high level i was meaning the high level safty switch of the externaltank pump wired thought the comms cable of the indoor as opposed to the 240v power for the pump

http://www.jupiterheating.com/little-giant-pumps/images/vcmaL.jpg

[aza]

Hi, whoever installed this system wired the pump to the power cable inside the indoor unit which comes from the outdoor which also acts as the comms cable.

Can i just say this is a great site and thanks to all who help out we lesser mortals with problems....cheers.

[ozairman]

The biggest thing to remember is that inside a Fujitsu unit a RED wire IS NOT AN ACTIVE!!!. On the cassettes and inverters and anything that uses 3 wire interconnects with a controller pcb in the outdoor unit uses the following colour code inside the unit

RED = Comms, signal wire
WHITE = Neutral
BLACK = Line (Active)

It is not unheard of for things like pumps or damper motors that are connected to indoor unit terminals to cause communication issues between indoor and outdoor units. As the comms wire uses the Neutral as it's reference using the top and bottom half of an AC sinewave to send info in each direction. Any interference from those things can upset the communication.

Can you explain exactly how it was wired and what model the cassettes were? I will have a look at some wiring diagrams and try and explain what was going on for you. Was it the power supply to the pump or a set of high level alarm contacts, that was wired to the indoor unit and to which terminal?

With the multiple sets of units from one controller there are also dip switch settings on the wall controller when multiple systems are connected.

[aza]

Hi ozairman,

The Aspen Tank pump power cable was wired into the same terminals that you connect the cable from the indoor unit to the outdoor unit.

Model AUY25RCZL or RZCL

The switches on the controller were ok.