Toshiba SMMS VRF - Indoors not getting addressed

[xyzeee]

I am facing trouble with a Toshiba SMMS system. There are a total of 14 refrigeration circuits and 2 of them are behaving in a peculiar manner.


When we try to address the system, some of the the indoor units cannot be detected by the outdoor.

Even if all indoors are detected, sometimes two or three of the indoor units will stop with E04 error on indoor side followed by E19-00 error on outdoor side. Any two or three indoors can get impacted.

The communication cabling is checked thoroughly. The earthing is checked thoroughly. The head unit was changed When nothing seemed to work all PCBs on the indoors and those on the outdoors were changed, with no result.

What could be the possible reason ?

[multisync]

you have not correctly addressed them

go back to the manual and follow the set up instructions

[martinw58]

check the conection plug between the fs box and the indoor unit is pluged in corectly thay can look like thay are corect but are not on pins corectl

[xyzeee]

Went through the manual one more time as suggested by you. Have addressed over 500 Toshiba SMMS systems over a period of last four years. Never faced any such issue.

Could you please point out something specific that we may be missing

[nike123]

Even if all indoors are detected, sometimes two or three of the indoor units will stop with E04 error on indoor side followed by E19-00 error on outdoor side. Any two or three indoors can get impacted.

E19 mean that you turned ON first outdoor and then indoor units. It must be turned ON first indoors and than outdoor units. Or you turned them ON simultaneously, or maybe you have problem with indoor units power supply.

Read carefully instalation manual.

[Davey 2 Pints]

Hi xyzeee
The logics of the Toshiba system are clearly struggling to maintain or address the indoor units, why this reason is for you to work on and find out, hopefully below will help you a little.

There must be a problem with either the network cable (U1/U2 cable form outdoor to all indoor) or potentially an indoor unit bringing the whole system down. I would be tempted to say the network cable itslef being the likely cause.
You say checks have been carried out on the network cable, so you should be in a position to answer these questions.
1. Is the C.S.A of network cable larger than 1.25mm and two core?
2. Is the cable screened?
3. Is the sceening twisted together at all indoor units, earthed at the condenser only?
The answer to these three question must be YES, if you answer NO to any then the errors certainly wont help your cause.
4. Are there any star points in the network cable?
Question 4 must be a NO

Once any cable issues have been cleared up then a faultfinding exercise is your next step.
I would attack this in one of two ways.
Firstly using the original network cable, disconnect all indoor units barring the 1st in the chain. So effectively this becomes a 1 indoor system only. Switch indoor unit on 1st then condensers, allow the system to configure itself and hopefully you will see U1--- displayed on the lead condenser after a short while.
Place rotary switches on main PCB outdoors to 1 4 3, the display on the same PCB will indicate number of indoor unit assigned to the outdoor, using the proceedure above you would expect to see 1 indoor unit.
Take this one step further and continue to add one unit at a time, each time you check number of indoor units it should increase by 1.
If one indoor is bringing the whole system down then this step by step proceedure will highlight the problem unit/s

Second option would be to run a temparary cable from the outdoor U1/U2 terminal bed to each indoor unit individually. checking each time that the indoor unit will successfully assign itself to the outdoor condensers. This proceedure will have the same end result as the first option.
I doubt very much your outdoor unit is at fault, what this does sound like is a network cable error or 1 indoor PCB bringing the whole system down.
Faultfinding on a system such as this isn't a 2 minute job, put the spadework in and you'll get to the bottom of it.

A few more questions for you, do you have central control on the systems or do you have 1 local controller serving over seperate refrigerant lines?

Good luck and let us know how you get on, if i can assist further then ask away.