Very strange City Multi Issues

[carrola7]

Having a very strange issue with a City Multi at the moment.

A bit of history first.

There was a building with a number of outdoor units (7 I think) all connected to a G50 and procon BMS modbus. They decided to build a wall down the middle of the office and split the City Multi systems between the two sides.

My job was to take three of the outdoor units off the existing system, install an AG-150 and recommission.

I disconnected the central controller connections at the three outdoor units and ran a new cable, daisy chaining the three units and connecting to my new AG-150. When I commissioned the system all seemed to be working well.

Fast forward a couple of months and new tenants move into the office. I get a call to say that two of the controllers are turning off of their own accord and one of the controllers has 'CENTALLY CONTROLLED' flashing on the screen and does not allow any of the buttons to be used.

The system set-up is as follows:

Outdoor type: PURY-P250YMF-C

Remote type: PAR-F27MEA

Outdoor unit: 051
-IC01, RC101 (Group 1 on AG-150)
-IC02, IC04, IC05, RC102 (Group 2 on AG-150)
-IC03, RC103 (Group 3 on AG-150)

Outdoor unit: 056
-IC06, IC07, IC08, IC09, IC10, RC106 (Group 4 on AG-150)
-IC11, RC111 (Group 5 on AG-150)

Outdoor unit: 062
-IC12, IC13, IC14, RC112 (Group 6 on AG-150)


I went to investigate the issues in the office and found various fault codes appearing:
1501- OC51
1501- OC62
6603- IC11

Now the two 1501 fault codes seemed to appear almost at the same time.

My first thought was that there is something wrong with either the central controller or one of the outdoor boards and the central controller is migrating the issues to the other units.

I went back to the three outdoor units and disconnected CN52 (central controller) at the outdoor board. I carried out a virgin restart on each outdoor unit and set them up as individual standalone systems, the theory being I could see where the problem was originating from.

That day the only problem with any of the systems was that RC106 turned itself off. I left them alone for another day (today) to see what, if anything, would happen. All three systems ran without any issues up to about 14:00, when it was noticed that RC102, RC106 and RC112 all had centrally controlled on the screen and did not allow any of the buttons to be used. Holding 'FILTER + ON/OFF' cleared the 'CENTRALLY CONTROLLED' from RC112 but the other two were locked in their current modes.

I cannot understand what is linking still linking these three systems together. I thought the only way systems could be linked together was through a central controller.

Have I forgotten something or am I ignorant about some other way the MNET can be linked between the three systems?

Any suggestions at all are very welcome. I'm completely out of ideas here.

[carrola7]

Edit: Its an AG50, not AG150.

[install monkey]

are any of the remotes prohibited on the ag50?- try unpluggin the procon incase the bms is causing issues

[install monkey]

1501 short of gas , 6603 transmission line busy
Transmission circuit bus-busy error
1 Collision of data transmission:
Transmission can not be performed
for 4~10 consecutive
minutes due to collision of data
transmission.
2 Data can not be transmitted on
transmission line due to noise
for 4~10 consecutive minutes.
Note:
The address/attribute
shown on remote
controller indicates the
controller which has
detected error.
Checking method and processing
1) As the voltage of short frequency like
noise is mixed in transmission line
continuously, transmission processor
can not transmit.
2) Faulty controller of generating unit.
a) Check transmission wave shape/noise on transmission
line by following <Investigation method
of transmission wave shape/noise>.
→ No noise indicates faulty controller of generating
unit.
→ Noise if existed, check the noise.
Checking
code
6602

[install monkey]

try swapping a controller, obv readdressing if req

[carrola7]

Thanks for the reply Install Monkey. I understand what the faults are trying to tell me but I just don't believe them to be honest. I had a 6607/6608/6600 issue referring to four different systems and about 20 indoors a while back that turned out to be one of the outdoor boards.

The thing that gets me with this problem is that THREE different controllers on THREE separate systems all started showing 'CENTRALLY CONTROLLED' at the same time. I don't really believe in coincidence.

I think the systems are somehow connected. I just can't figure out how.

[install monkey]

yep some faults can give you the run around- had a mitsi no alarms- 1 unit not performing- bloody fan motor plug unplugged- lev was modulating off the pipe sensor- all appeared ok, doesnt alarm on no airflow on a ducted unit

[marc5180]

If the controllers are turning off on their own accord then you have either lost mains power to the indoor unit or the unit in question is also being controlled from somewhere else (maybe another remote controller or even the BMS)
Are your faults appearing on the local remote controllers or are they from the AG50, if they are from the AG50 then disconnect this including the power pack to see if this is causing the issue.

Are the 3 systems that you have rewired and addressed still connected to the BMS and if so is this where the conflicting addresses are coming from?

Is there any way that you could have a ghost address in there somewhere because they can give you all sorts of weird issues.

Lastly when all 3 of the outdoor units are connected do you only have one of the CN51/52 set to master and not all 3 of them?

[carrola7]

The units turning themselves off is happening less often than the 'CENTRALLY CONTROLLED' issue so I would be happy to disregard the power issue for now.

I agree with you that it could be controlled from somewhere else but I can't figure out how. I have taken all three systems off the central controller by disconnecting at the outdoor units. How else could they still be connected to the BMS? Where along the MNET transmission could one conceivably connect it to a BMS system?

I checked all the remotes for ghost addresses and carried out a virgin restart on each system after removing the AG50. Another point to note is after restarting a system it is necessary to manually programme each indoor. None of the remotes are picking up their indoor units.

Not sure what you mean by your last point (CN51/52 set to master).

[Neddy]

Have you got 3 wire cables plugged into the indoor PCBs. You can have a window switch or light switch wired into these to switch on the AC units but they will show centrally controlled if say a window was opened( just an example) . Have you checked the group setting on each PAR-27 controller to make sure they are controlling the correct address? IE RC 102 controls Indoor address 2,4&5. Any other cable in the G50 USB etc?

[marc5180]

Sorry I meant CN40/CN41 not CN51

Do you have any interfaces connected to the indoor units such as key cards?
Is the procon connected to the Ethernet?

[5H86User]

Look for noise on your control lines. You could have AC ripple being superimposed on the control lines, which tends to interrupt the control lines. You can look for it with a scope meter.

Eliminating it can take several possible methods - separate the power and control wires, or shield the control wires (crinkled up aluminum foil works - not smooth), or put in a filter if the OEM allows them.

[carrola7]

Holy sh1t Neddy I think you might be on to something there. As far as I can remember there are indeed window sensors installed in the indoor units.

I'll check it out next week and let you know.

Thanks to everyone for having a think about it.

[carrola7]

UPDATE...

So I went back to site on Wednesday morning and sure enough found window sensors connected to the indoors. Disconnected them and system has been running fine since.

Thanks again Neddy and everyone else that contributed to this thread.

[regcooldude]

IC 6/7/8/9/10 should be in group 6 on the ag50 not 4
IC 11 should be in group 11 not 5
IC 12/13/14 should be in group 12 not 6
this will affect the Procon set-up if not put right .