Mitsibishi VRV Question?

[moondawn]

hi all,

i have a job starting next week, there is a mitsi vrv that i need to decant. it is a refnet system. my boss wants me to reclaim the gas from the system and take out one unit. the unit on the remote controller says its address NO 3

i have no drawing or plan off the system, i think there is more than 3 units on the system.

my question is: if i was to take the unit out and link the two interconnecting cables from that unit together in a junction box, would the rest of the system still work ok with no communication errors??

thanks in advance moondawn

[Freecool]

The answer is yes it should do. but if its the last one on the circuit you want have to. If the unit is the middle of the link you will have to re address the system on the indoor units. Dont forget turn off indoor units first then outdoor.Vice versa when bringing the system back up. Also when reclaiming make sure all the valves are open.

Good Luck
Freecool

[moondawn]

If the unit is the middle of the link you will have to re address the system on the indoor units


the address is no 3 so its likely its in the middle.could you explain why i would have to re address them.

if for example it has six ac units add1 to add6 i take out add3 and link the cables would the m net not by pass add 3 and skip to add 4 automatically and continue to work alright?

thanks for your imput mate

[marc5180]

On some of the multis that i have worked on, the indoors have dials near the indoor PCB where you set the addresses, so if you take out no 3 then switch it back on the condensor will run through the checks and count 1,2,4,5 and 6 so the addresses will need to be changed

[The Viking]

What model are we talking about?

[Freecool]

How old is the system, Have you got the models of outdoor and indoor.
Say there are 6 indoor units 123456 and you remove no4 you would have to re-address the system 12345 so the original no5 will become 4. and no6 will be 5.

Freecool

[stuartwking]

Model Numbers would help us all out.
I recon you WILL have to re address your indoors and dont forget your virgin restart...

[declan simmonds]

Hello dawnmoon
first of all it doesnt matter what the address codes are for the indoor units i think you can address them from 1 to 50 as long as you dont address two units the same number,
as marc1850 said switch of the indoor units first and then outdoor unit. remove the fan coil or cassette etc join the comms wire to link the units and then switch on the indoor units and then the outdoor units the outdoor unit will only look for units that are there that have address number.

[moondawn]

i have no model numbers for the equipment. i am pretty sure its r410a system from breifly seeing the outdoor unit from a far.

i was thinking the way declan was. i have worked on some systems where the would have fifteen indoors addressed 1-10 and then 14 15 16 17 18 i gather they left address 11 12 and 13 cos they could be added to the certain floor at a later date.

anyone else reckon they know for sure?

cheers for the replies lads

moondawn

[Thermatech]

Moondawn

Using the engineers mode on any 30v Mnet remote controller you can find out the address of every indoor unit , remote controller & outdoor unit in the system.
You just need to read up the service manual to learn how to do this.
By using this method you can find out how the indoor units & remote controllers are set up.
If the unit is one of a group of indoor units being controlled from the remote controller you might need to make some address setting changes but if the indoor unit is the only unit being controlled from one remote controller then it can be removed without changing any other unit address settings. Just link the Mnet control cables when you remove the indoor unit.
However the outdoor unit will not forget that it has an address 03 indoor unit in the system & so when you power up the outdoor unit again it will look for 03 but wont find it so will show communication fault for 03.
To make the outdoor unit accept the new configuration of indoor units you need to carry out the 'virgin restart procedure ' with the Sw2-2 dips on the outdoor unit circuit board. This clears the outdoor memory of connected units address settings & makes the memory blank as when it was first delivered from the factory.
Always do this procedure when making any address changes in the system.
BTW on the very very old YM outdoor unit from about 1992 to about 1994 there was no virgin restart available & you had to leave the unit switched off for about one hr which could be a real problem.

If you have a central controller the unit & remote controller will need to be deleted at the central controller other wise it will not get any communication reply from 03 & will report a communication fault.

If the system is stand alone system for instance you could made the indoor units 01, 02, 03, 048, 049, 050. You would just need to make the remote control address settings to match the indoor units & then do a virgin restart. The outdoor unit will then comunicate with these indoor units the same as when they were 01,02,03,04,05,06.

9 times out of 10 no need to make any other address changes to the address settings of any other units.

[moondawn]

hi thermatech thanks for your detailed post.

what you have said is what i was thinking . i own a laptop with the mitsi software so i can plug that on to the m net to check all the indoors and remotes and it it has a g50 or trend. As far as i can see the unit that is being removed is in a small room on its own, and it has its own remote controller. so with what you have said as long as i link the comms cables together and do a virgin resart all should be ok.



i will update as i carry out the work

thank you all

moondawn;)

[moondawn]

i have now carried out this job.

First of all i deleted the remote controller from the system this is done by Holding down filter and swing lover it then brings up this ---

then press clock button and it shows -03 IC
then press clock on/off button twice and it deletes it from the system and the controller starts to HO.

after decant pressure test and joining M net cables together etc. I gasssed it up and ran on test run. I did not have any problems with the system all seems to be working fine and seems i did not need to change addresses on the system


cheers Moondawn