View Full Version : Toshiba VRV

07-04-2004, 07:29 PM
Hi Guys,
2 compressors in this unit,is one of them contolled by inverter?how do i go about testing them? is it the same as a electrical motor ?can i put a megger across it? any info please.

07-04-2004, 07:51 PM
what are you testing 'for' ?

you can test a compressor in the normal way for winding condition..
however remember if you megger the inverter board it will blow..

comeback and give us a proper description of whats going on here...



08-04-2004, 05:12 PM
Sorry mate, the VRV keeps tripping out it`s controlled by toshiba interactive intelligence software ,there are 4 ceiling units connected to it and when i ask it to work hard it goes out on high pressure switch tripped or abnormal inverter fault someone suggested compressor problem???? :mad:
Frank McBride.........

08-04-2004, 05:31 PM
is it running in heat or cool?

bit difficult to diagnose but make sure condenser is clean and filters are clean.

then fit your gauges and watch the compressor on the hi side -ramp it up till it trips -this will narrow it down to this (providing the hp itself isn't dodgy

then come back

alternitively phone toshiba technical when on site and they will talk you through..



08-04-2004, 07:17 PM
hi frank,

I'm not much help in VRV but it looks to me that the compressor is fine, the problem could be, as richard said, dodgy HP control.

remeber that high presure switch is protecting compressors from drawing high currant.

overload protecting compressors from high currant or low voltage.

I suggest from reading only that the problem is elsewhere.


09-04-2004, 10:22 AM
Not overfilled in the winter?

09-04-2004, 05:11 PM
Thanks again guys,i`m electrician finding my way so using a set of gauges is not a strong point although i do have them to use if need be ,the unit trips out on both heat & cool but if i switch two of the five ceiling units off it seems to cope!!! :(
Frank McBride

09-04-2004, 05:47 PM
get an amprobe on and take some readings -then switch on indevidual units till it trips...can be very difficult confirming inverter drive c.b and /or compressor..



09-04-2004, 06:11 PM
High pres cut out, :( non condensibles come to mind, may be a poor installation

09-04-2004, 09:06 PM
To test the inverter, check the noise filter and make sure you have power in and out and check the fuses. Test the resistance in and out of the reactor and make sure that the converter is putting out power to the compressor. I assume it's three phase so check the resistance across the terminals (with the cables removed) it should be the same. If the systems going out on HP them it's unlikely to be a fault with the compressor. It's usually the system failing to get rid of the heat-in other words a condensing problem. Maybe non condensables, faulty HP control, condenser fan etc etc. Check the temps on the pipe in and out of the condenser. This will give you an idea of heat rejection in the condenser. You can check the compressors current draw, but do not put high voltage (such as from a Megger) through the inverter. I don't work on huge amounts of Toshiba VRF, but assume there isn't much product difference from Daikin, Mitsubishi and Hitachi etc


09-04-2004, 10:13 PM
Thanks guys ,you have given me plenty to look at ,the system was installed 18 months ago i have about 70 ceiling mounted units & 18 or so VRVs so any info you guys put my way is brill,Tosh warranty is now up so i`m left holding the baby ............
Frank McBride :)

09-04-2004, 11:16 PM
Thanks guys ,you have given me plenty to look at ,the system was installed 18 months ago i have about 70 ceiling mounted units & 18 or so VRVs so any info you guys put my way is brill,Tosh warranty is now up so i`m left holding the baby ............
Frank McBride :)

............Toshiba's warranty in the UK is 3 years.

Why not give them a call?
Ford Performance Vehicles specifications (http://www.ford-wiki.com/wiki/Ford_Performance_Vehicles)

14-04-2004, 11:02 AM
hi guys,

sorry to but in but can anyone tell me wat a VRV and a VRF is?



14-04-2004, 11:54 AM
Paul, they are both terms for exactly the same thing.

They mean ?Variable Refrigerant Volume? and ?Variable Refrigerant Flow?.
The former has been registered as a trade name, I believe, in Europe by Daikin. The latter, VRF, is a generic term for what I am going to describe briefly below.

In origin it is a Japanese product that consists of a large number of DX indoor units. They go up in multiples, 4, 8 16 even 32 indoor units on one system, or any number to suit in between.

It can be Cool Only, Heat Pump or simultaneous Heat / Cool where the heat rejected from units in the cool mode is put back into the building instead of being rejected outside. Crazy as it sounds, this is a very viable product in Northern Europe, where many large commercial buildings can be net producers of heat, especially in the central core. They are a serious challenge to chillers in many areas.

It works with an Inverter driven compressor and the refrigerant is metered to each indoor coil exactly by electronic expansion valves. These systems are capable of huge energy cost reductions if they are designed and installed correctly. Not only that, they are almost infinitely flexible if the building layout or use changes.

If you want to know more, there are numerous UK web sites detailing their operation mode in more scope.
Sparta (http://www.honda-wiki.org/wiki/Honda_Sparta)

14-04-2004, 12:02 PM
Hi Paul

Basically they are the same thing. Daikin call their system VRV (variable refrigerant volume), and the title is copywrited so all the others have to use the title VRF (variable refrigerant flow). Samsung have their version called a DVM (digital variable multi).

Each condenser has multiple evaporators. The speed of the compressor is varied by an inverter (except Samsung) to match demand (hence the name).

Hope this helps

14-04-2004, 08:19 PM
Hi Argus

On the new Daikin VRV II you can connect up to 40 indoor units to one outdoor unit.

Marvellous piece of kit. The new VRV II even tells you if it has a refrigerant leak and shuts itself down! :)

14-04-2004, 08:45 PM
if i switch two of the five ceiling units off it seems to cope!!!

That certainly doesn't seem like a compressor fault or a HP fault.

Has the system operated correctly in the past? Could the system be incorrectly designed? Has the maximum pipework length been exceeded?

Do the indoor unit's capacity (index) exceed the outdoor unit's capacity? Post the system details and I'll let you know (model numbers).

All sorts of questions come to mind.

15-04-2004, 06:49 PM
Hi Frank,
The plot thickens!!!!!!!!! above the ceiling there seems to be some kind of marshalling box with a lot of pipiework looks like solinoid valves opening and closing a low squealling noise ,wonder if one or more of these valves is jamming open or close ,VRV icing up badly at times are heating solinoid jamming?
Frank Mc Bride

15-04-2004, 07:21 PM

It's the multi- controller. It contains all the solenoids and electronic expansion valves for the circuits attached to it.

It also has a self diagnostic feature on the PCB that will tell you what's wrong with it, but you will need to know what the codes mean.

If you get the model number and search Toshiba's UK web site you sjhould be able to down load the service manual.

You are wasting your time without it.

You could also call Tosh in Leatherhead they should be able to talk you through it.
Toyota eCom specifications (http://www.toyota-wiki.com/wiki/Toyota_eCom)

15-04-2004, 08:30 PM
If the unit is in heating mode and working hard then you will find that the outdoor unit ices up periodically. This is quite normal. The unit will defrost itself so don't worry.

What leads you to the conclusion that the system is not working OK? Are the rooms at or near stat set point? Is it just because the system makes a noise?

VRV/VRF systems have advanced electronic controls and seem not to be working as we usually understand them but 9 times out of 10 they are. Check the basic stuff first - is there a fault code showing on the controllers? can you feel heat being rejected/cool air being discharged? I think more information is needed. :confused:

Feargal Loy
11-11-2006, 12:18 PM
possibly overcharged, decant entire system and re charge, doing calculations for pipe length. is main run to BC box exceeding maximum allowable length? check all illet/outlet temperatures with the system running at full load.

on heating, inverter takes control input from discharge pressure transducer to maintain a target pressure, suction pressure transducer on cooling. possibly faulty transducer, run all units flat out on heating and record high side pressure over a period of time, if too high then possibly faulty transducer or outdoor unit board. its also possible that this is happening during heating startup if the EEV at the outdoor unit is not opening quickly enough.
is the system SHRM or SMMS? silly question but are all the shutoff valves open?

VRVs are not the easiest thing in the world to diagnose first time (see above list !)

as ARGUS said, get yourself a copy of the manuals, you might as well be attempting to fix a space shuttle without them.

hope this helps, best of luck

12-11-2006, 05:52 AM
Normally indoor units are selected for a capacity 130% of condenser in VRV. But, one thing is to be taken care - All in indoor units should not be operated in maximum capacity simultaneously. This is done in locating the indoor units. IDU should be located such that the peal heat load timing should not match. If it happens, that also in peak sumer, the discharge pressure will go beyond the HP switch setting.As the compr tripping is on HP, no chance of any compr fault.
Other factors such as choked condenser coil, faulty condenser fan, im-proper evacuation, overcharging of refrigerant etc can also lead to tripping of compressor on HP.

12-11-2006, 08:53 PM
I hope he managed to fix this unit as the post was dated back in 2004:p
Maybe Mr.Mcbride would care to inform!

07-02-2007, 07:53 PM
Hi Guys,
2 compressors in this unit,is one of them contolled by inverter?how do i go about testing them? is it the same as a electrical motor ?can i put a megger across it? any info please.

hi frankie...has this system got 2 compressors in the one shell???? if so, problems with those compressors i have come accross.. i recommend checking compressor windings for balance and earth leakage...i came acrosxs alot of earth leakage faults causing internal clixon to be active when voltage is increased from inverter which is in series with a head pressure fault ....why not watch head pressure whilst running and if nothing is abnormal, disconnect inverter compressor and let run on d.o.l..me thinks you need new compressor

Brass Monkey
08-02-2007, 10:53 AM
Hi guys new to the scene.
If its the model i am thinking of the condenser fans are variable speed (inverter). These may not be reaching full speed due to faulty tranducer on HP side of system. Part is in a nice place to change out. Do you have a fault code?.

Regards Peter.