VRV Mitsubishi wiring

[kvas]

Hello, i will install two systems of mitsubishi vrv with a centralized controller. The question is this: can we install the communication cable to a star topology or single in order as described by the manufacturer? to explain more, all pipes will be under the floor and only solders above this with a collector, therefore, it suits the communication cable to run with pipes without any further digging. i am sorry for my english.Τhanks in advance!!!

[install monkey]

centralised controllers connect to outdoor unit on terminal t b 7

[stufus]

I'm not too sure what your asking here !
The M-NET line is just a big daisy chain and can be spliced any where providing polarity is maintained to avoid the possibility of dead shorts.
As install monkey says the central control line is separate and connects to both outdoor units on TB7 and continues to controller location.
If pipes and control cables are to be buried they will need to be sleeved in Wavin pipe or something similar .
If power cables are to be buried also they should be buried in a separate trench to avoid induced interference with communication cables.
Double and triple check all connections to be buried BEFORE they are sealed in !!!!!
For obvious reasons
Cheers
Stu

[csdome]

hi.
the communication of indoors and outdoor unit make only chain topology . do not use star. like in install manual. The two system connectting with the other connector. see the outdoor adresses . do not set to same to two systems. The power supply of a two system' cable is make the smallest address outdoor unit with a connector. I will send a drawing if you need tomorrow. What is type of your central controller?
regards.

the click on the thanks button does not pain

[kvas]

Thank you for your replies, csdome you understoοd exactly what I ask and ok.. I will not try star topology. the central controller is PAC-YT40ANRA.Power supply unit is necessary.?? Someone says no, some..yes!! Any help and diagram is acceptable and thank you. Stufus , As for your advice on cables I'll try to be sure about connections before bary it under the floor and I'll use flex pipe to sleeve my cables. Thanks again for your advice.

[JoeAT50A]

You could able to have a shared power from one of your outdoor unit (say OD-1) via chage jumper from CN41 to CN40 which is located OD's main controller board upper right corner. But by doing so, if your OD-1 down or power failure then your centralized controller will black out. Best is to have a power supply unit PAC-SC51 KUA or PAC-SC50KUA (previous model). I have no idea which one is available in your country.
Here is the URL for installation Manual. Good luck in configuration
http://www.mylinkdrive.com/CityMulti/Controls/Accessories/System_Controllers/PAC-SF44SRA_Install_Manual.pdf

[csdome]

Hi Mr kvas.
The drawing of LoeAt50A is good for you . the poer supply of communication between 2 systems make the short circuit stecker change CN41 to cn40 on the smallest adress outdoor unit.

The PAC-YT controller can you connect anywhere on M-net transmission line. Anywhere like if you see the th cable or connector. just clean and connect. The address of PAC YT must be a smallest addres of indoor+200 (eg. 201)

[techguy]

HiKevas

In the past when I worked on Mitsu Kit we used to run M-Net cables back to a central point junction box. Then
Connect each indoor units to two seperate din rail mounted connectors. Each pair of connectors was then looped to a common set serving the outdoor units. Not exactly star but very close to it.

This always worked fine.

With Sanyo we can do similar but we recommend no more than 3 units to any star point and 1mtr of cable between each star point.


T

[kvas]

Techguy Im trying to anderstand you.. actually you said something like that?? http://pdfcast.org/pdf/like-star-topology but this is a chain topology with much more mtrs of cable..

[stufus]

http://www.structuredwiresystems.com/Pages/daisy_star.htm
kvas
If you look at the attachment example 1 represents the Mitsubishi daisy chain (i know it's phones but it's all i could find)
What Techguy is saying is it can be done as per example 2 if you take it the Phone company location is a junction box.
In that junction box are two ,for argument sake ,busbars 1 for M1 and 1 for M2.due to the space restrictions at the terminal blocks in the mitsubishi range it can be tough to fit in two 1.5 cables for the transmission line plus a 1.5 0r .75 for a controller .
We have all been in the position of trying to check or repair the wiring on one of these through an access panel you can barely get your hands through.
So running all connections to a central point means there is only one transmission line connection at each unit reducing the chance of wiring problems.And any wiring problems that do arise can be easily diagnosed from a central position.
Therefore the junction box acts as the hub of a star topology while actually being the centre of a daisy chain.
I hope that's clear enough for you to grasp
Cheers
Stu

[JoeAT50A]

Sometime you may need to have blends with chain and star combination.
It depends, I always used combination as long as shortest route.
Star connection more wiring works and chain is simple loop (shortest route most of the time). But you have to take care of Mnet limitation in lengths (200m/500m).
Within limit you could able to use either one.

[r0ss]

I always daisy chain any VRV/VRF system.

Ive been to look at sites with star wiring and its always complete mess with the cables going everywhere with no order.

So much easier and efficient to work methodically in my opinion, even if it is the longer way round.

[stufus]

Funny that as if star wiring is applied "it's usually the long way round ".
The state of the wiring is down to the installer not the application.
If it's installed methodically where's the problem.
The reason you always wire in daisy chain is not because you choose to do so, it's because the manufacturer has chosen that format as a base standard .
But all manufacturers will tell you star is an option however each will specify their own limitations to the application.
Cheers
Stu

[csdome]

Hi.
in Mitsubishi VRF can use only chain, wiring to outdoor-indoor-indoor communication If you have too many meters, then you can use an amplifier box in ewery 200 metres. be sure the diameter of wiring. See Mr Stufus. The M-net remote controller can connetct ewerywhere and can use thin cable.

[stufus]

Hi.
in Mitsubishi VRF can use only chain, wiring to outdoor-indoor-indoor communication If you have too many meters, then you can use an amplifier box in ewery 200 metres. be sure the diameter of wiring. See Mr Stufus. The M-net remote controller can connetct ewerywhere and can use thin cable.

You are missing the point
The daisy chain does not have to go ...OC-BC -IC-RC etc etc ...(read up on fuzzy logic)that is merely a guide !as it's a chain it can take any route so long as the chain is not broken grounded or shorted.
I am well aware of all the Mitsubishi guidelines and specifications regarding wiring and cable sizes and limitations,as I have worked for Mitsubishi Electric in the past.
BUT...Guidelines are exactly that guidelines, as there has to be a base standard to facilitate a standardised training program.
If you wish to believe there are no alternative variations to the standard which can maintain the integrity of the chain that's fine.
I'm not trying to tell anyone how to do their job, just offering on opinion on a viable alternative.
As I said in my last post .each manufacturer will specify their own limitations to the application ! and certain core limitations must be followed.
Cheers
Stu

[kvas]

thanks everyone.. i think that after your opinions is better to use a daisy chain as manufacturer says. i must be sure because the floor of this house is so expensive as my all house!!

[kvas]

Iam back again .. i ask MUI if i need power supply and they told me that if i have two outdoor units i dont need. They didnt want to explain more. Can anyone tell me what is going on with that thing? i will install PAC-YT40ANRA and there is two pumy p140. This central need 24v ? My technicians said that never before have installed mitsubishi power suplly at this central controller.
If not need it at last it will be a problem to join the transmition cable that i have cut to insert the power suplly or i'll have some loss and i need something exceptional? Thanks in advanced!!

[JoeAT50A]

6554You could able to share the power from one of the outdoor units via changing CN41 to CN40 (jumper adaptor). Attached picture is factory defult, you need to change.
Only one will do let say you share the power from OD-1 (PUMY-P140) but you have to accept the situation when OD-1 has power failure, then your ON-OFF controller (PAC-YT40) will black-out.
You have two outdoor units, your risk is 50/50 chance. Up to you to decide whether you could use power supply unit or not.
Hope that will help.

[kvas]

It was so easy... why they dont tell me??? thank u a lot JoeAT50A!!

[kvas]

Back again.
Manual says (PUMY) that we must turn on outdoor units 12 hours before. I have not yet installed controls. Can i turn on at this situation the outdoor units for oil heating or must be complete.
Here in greece we have 20-24 deg C. It is important to do that for 12 hours? Im asking that because of limited time.
Thanks in advance.

[moondawn]

hi there, when switching the power on i normally disconnect the mnet so that units are not accidentially switched on, this can be done by simply disconnecting the mnet connections at outdoor condensor

[kvas]

Thanks a lot, therefore it is not necessarely to be ready from controls to heat oils. I tried to switch on today and was making a strange noise that scared me and i cut it off. I will do it as you telling me for 3-4 hours and i believe will be enough.

[moondawn]

yeah its just for warming the oil in the pot i done plenty of times just disconnecting mnet crannkcase heats the pot, then switch off connect the mnet and switch back on.

[kvas]

Thanks Moondown..!!!!

[JoeAT50A]

Good practice wise, you have to follow the law.
Have to turn on at least 12 hours to warm up before test run. If not full of liquid in compressor especially for low ambient conditions. That liquid compressing effects might damage a scroll compressors.

But in practical, especially with tropical conditions like above 20 degree C, most of the people (tech) won't bother about oil heating. After evacuating done, then straight away turn on the power and open the ball valves and test run. Then make a refrigerant adjustment by weight later. Only they takecare when they release the ball valves.
They release the ball valves very slowly to make sure the POE oil to be inside the compressor. If you release immediately, then oil will be come out from compressor and accumulated at indoor units before test run.
If so, result of lack of oil in compressor will make some strange noises (you mentioned).
What we normally do is to charge some refrigerants after deep evacuating, and also release the valve slowly.
Very safe.
If you can't wait 12 Hrs, please measure the compressor shell temperature, and found above 20 Degree C then you can do the test run safely.
Hope that will help.

[kvas]

Thanks Joe! I did it as you described and everything went well!
An other question is if you know, when we have a central controller (Pac yt 40 anra) and a group (as 007,008,009 with a remote 107) how can we register at the central remote? I registered 107 at one button and controlled only one. Then i registered not the remote controller but the units (as 008 and 009) at the central controller too, and works. Is this right or i must do something different to fully control 3 units with one remote?

[JoeAT50A]

You have registered the 007, 008 and 009 with normal remote 107. It's called a group named G07.
When to assign on YT-40ANRA, there is only one group cum one button named G07 consist of all 3 (007 to 009) unit. You can't able to have individual three buttons for sure.
Hope that will help.

[kvas]

Joe, when i registered at the remote control only, 3 units was controlled. Then i tried to register at the central control the remote (107 at one button) as i did at any other unit (105 for 005 etc.) but know only one unit (007) controlled. I registered 107, 008,009 to success contol.
You suggest to register units only and not the remote at the central control?
Sorry for my ignorance

[JoeAT50A]

I bit confused after all, what we I mean is this (refer to attached pictures)
I have following configuration
001 with 101 (individually) so called Group1
002 with 102 (individually) so called Group2
003 and 004 with 103 (as a group) named Group3
And 007,008, 009 with 107 (as a group) named Group4
Then PAC-YT40 can able to register maximum 4 buttons for Group 1 to Group 4.
For my case I can't control or assign buttons for 004, 008 and 009 and can't able to control individually.
for example you assign button no4 for group 4 consist of 007,008 and 009, then whole group will same time ON, same time OFF with same settings.

You and me are confusing with grouping ... normally PAC-YT40 are some sort of group controller. To contol 16 Groups (16-buttons) or total indoor unit mas 50 units.

6721

[kvas]

Exactly this is the problem, when i register group 4 only one (007) controlled.
But before connecting the PAC YT40 group 4 controlled fine by the remote controller.
I will clear all address and i'll do it again, something happened.
(when i register at the ON/OFF controller the address what i have to register is 107 , ok ?)

Joe you and other engineers in this forum help me throughout the installation and i have to thank you. I hope it will in turn to help other members.

[JoeAT50A]

Hi kvas,
Not at all, you are most welcomed.