mitsubishi controller G50

[sork]

hi lads , taken a mitsubishi multi city job lately, two indoor units not operating , cleaned filter, still no luck . one local remote displays H O i do not know what that is? the remote is locked.
the other local remote goes off after 30 second.
i tried central controller but after i enter ON position it goes to OFF position after 30-second
checked malfunction monitor
it reads: page 01/01 no error.
any help?
happy new year:)

[Contactor]

'ho' indicates the controller cannot locate the unit(s) or group it is supposed to be controlling, there's lots of reasons why this could be happening.

You will need the operation manual for the G50 from the Mitsu website.

You need to work out the system layout and unit addresses, this may take a while unless you have a diagram from the comissioning engineer.

[marc5180]

When the controller switches off after being turned on, this is usually caused by no power to the indoor unit maybe because of a blown indoor board, or the fuse spare blown.

When the controller flashes "HO" this is because it cannot communicate with the indoor.
As Contactor says you need to check the address settings on the controller.

[r0ss]

As previously said by the chaps above.

The remote switching itself off after a number of seconds = power issue to the indoor unit. I always find that its usually the spur that has been switched off by a sparks when they do their testing :confused: But check for 240v on the indoor

For the HO unit. Ensure all wiring / dipswitch settings are correct.

Mitsi VRF's are temperamental beasts at the best of times

[Thermatech]

The remote controller flashing HO has not been able to carry out electronic hand shake with its indoor unit or group of indoor units.

PAR27 with 30v dc control cable & address ?
For individual control of one indoor unit the remote controller must be the same address of the indoor unit.
For a group of indoor units it needs to be set for the smallest indoor unit address in the group.

G50 central control
The central control is the master controller & the indoor unit & remote controller have to be set up in a group. If someone forgot to assign the remote controller to the indoor unit for that group in the G50 group settings
then the remote controler will just flash HO because its not getting any instruction from the G50 master controller to carry out an electronic hand shake with any indoor unit.

This often happens when some one installs an extra remote controller but forgets to change the group settings to match at the G50. The next time there is a power cut the new remote controller does not get any instruction from the G50 when all the units re establish communications.

So you need to
1/ check address of the indoor unit.
2/ make sure the remote controller is the same matching address.
3/ Use engineers mode at G50 to check setup the group settings for that indoor unit & remote controller.

This process tends to be a bit easier if the O&M manuals have installed layout drawings with schedule of indoor unit address settings.

[sork]

hi there happy new year and thak you for your help.
i was on that site today:
its a multi city
one of the comp for a group is not working
i have power for indoor coil 1 and 2 and no power from 2 to coil 3 and ,4,5,6..
the HO was at unit 2
the local remote controller is: PAC-SE51 CRA
do i need to register all the group in each local remote or only one?
when correspond( shake hand) btw local and g-50a central go off( normal) does not stay reverse.
best wishes for all eng
sork

[jimibdn]

Hi,
H0 also means "no configured" you can see in a commisioning of a SF44 or YT34 or something else. you can set the RC adress from the PARF27. I guess that is a PARF27 because it remains 30seg on and then OFF...
If the parF27 goes from on to off in 30seg aprox it is possible that the indoor unit or the BC is out of power (220VAC).
Regards.

[troymedhurst]

I had same problem and found no 30vdc on comms at units. I checked at outdoor unit and had 30vdc going out. I eventually found a break in the cable- repaired and now all ok. If you can run cable from unit 2 directly to unit 3 (comms) If that works you know theres a break between 2 & 3

[jimibdn]

Hi again,
First of all: What kind of thermostats are conected? I thin PARF27... It´s a R2 system?
If all thermostats go off in 30seg aprox, please check input power to indoor units and BC ( if is a R2). For the H0 trouble i recomend you to check the instalation manual of PARF27 to learn how to make the config by software of the indoor units.
The PARF27 and the indoor unit have to have the same adress. When you try to match the indoor unit whith the PARF27 you have to see "IC" in the thermostat..If you see "88" you have a trouble with that indoor unit or the indoor unit don´t exist.