Help required regarding this AMAZING Problem In SET-Free Unit, Hitachi

[AbiBrl]

Hi,

Greetings to all

I have a problem regarding the set free unit oh Hitachi. The system have 5 indoor unit among which 4 are ceiling cassette and one is wall mount ac. The problem is when we start the unit the wall mount only gives the cool air and non of the other ceiling unit give cool air. The ceiling unit just run the blower as if the setting is in fan mode. But when we run the unit in TEST MODE then all the unit throw/blow cool air ( or hot air). Can you guys suggest the troubleshooting procedure.

Thanking You in advance

[frank]

Make sure that the controllers for each one is set to the same mode. If you want them all to cool, set all the controllers to Cool. If they are not in the same mode as the Master controller (the 1 that does the heat / cool changeover) then they will stay in 'Standby' while the Master is cooling,

[install monkey]

return air sensor holding it off? hold the check button to see sensor values on the remote controller- what model is it? test run just overrides the return air/room sensor

[AbiBrl]

hi

I have tried with the settings of the controller, turning on the indoor does not automatically starts the outdoor unit as it should have. If we give power to the wall mount unit then only the outdoor unit/compressor starts otherwise it does not(in normal case). The unit outdoor is RAS-4FSVN1Q and the indoor ceiling cassette is RCI-1.5FSN1Q,RCI-1FSN1Q, and RCI-2FSN1Q. The problem aroused shortly after the earthquake so is there any possibility that the vibration. Is there anyway we could check what are the other parameters that are bypassed while running in test mode.

[Brian_UK]

Check the wiring at the units.

[AbiBrl]

Check the wiring at the units.

I have checked all the wiring for the units they seems fine because if we unplug the wire then in 7-segment the error get display and if we interchange the connection then also the unit finds the fault and shows us the error number so that we can rectify the mistake. I tried the PCB of the indoor ceiling cassette unit in another site and the unit had the same problem so we guessed that there is a problem in PCB and ordered new sets which are also not working in those units.

Do you guys have idea how to check the PCB, I have tried troubleshooting the PCB through wired remote but the remote does not shows any defect in the PCB.

If you guys can suggest how/which components or parts to check that has been bypassed during the test run i will be very much thank full. I have replaced the return sensor as suggest by monkey but unfortunately i was unable to check the value from the controller... i will update the value as soon as i get it.

[AbiBrl]

Just to be sure these are the unit model numbers
No model serial no
1 RCI-1.5FSN1Q QCA96X9M0149
2 RCI-1.0FSN1Q QC916A5K0010
3 RCI-2.0FSN1Q QCA98X9M0144
4 RCI-1.5FSN1Q QCA96X9M0150
5 RAS-4FSVN1O QS682N8J0003

[frank]

Just to be sure these are the unit model numbers
No model serial no
1 RCI-1.5FSN1Q QCA96X9M0149
2 RCI-1.0FSN1Q QC916A5K0010
3 RCI-2.0FSN1Q QCA98X9M0144
4 RCI-1.5FSN1Q QCA96X9M0150
5 RAS-4FSVN1O QS682N8J0003

According to the capacity tables, you have a mis-matched system.

The maximum total capacity connected to a RAS-4 is 5.2, and you have got 6.

Here is a link to download the service manual in PDF

[AbiBrl]

According to the capacity tables, you have a mis-matched system.

The maximum total capacity connected to a RAS-4 is 5.2, and you have got 6.

Here is a link to download the service manual in PDF

Yes it is but we have reduced the capacity of the indoor using the settings in PCB to match the outdoor capacity.
Regarding the issue i have changed the PCB of one of the faulty to the other normally working unit in another site the problem still exists then when i replace the working unit's pcb with its own it works normally. We checked the wired remote for the error when we had faulty unit's pcb there also it didnot showed any error and worked properly in test run mode.

[AbiBrl]

Today i went to the site again and found something unusual. I was accompanied with one of the electrician to the site where we measured voltage and there was something unusual in frequency it was running from 35 to 123/130 . I dont know wheather his clamp meter is right or not but if his clamp meter works fine, then sudden fluctuation of frequency might have resulted our PCB malfunctioning. I dont know much about it yet if i know much further i will post it

[chemi-cool]

You can not measure frequency with clamp meter.
frequency can only be measured between phase and "0".

[AbiBrl]

You can not measure frequency with clamp meter.
frequency can only be measured between phase and "0".

yes we did check the frequency with clamp, since the reading was so unreal that we doubt the working of clam pmeter itself,

[install monkey]

you can only read comp current at the incoming power to the outdoor RST terminals- not on the lead to the compressor uvw as your clamp meter cannot detect current accuratly

[install monkey]

read compressor current,comp freq on either indoor remote controller via the check button or the outdoor pcb on the push buttons

[keapog]

If i understad the system is multisplit type . In most recent such system the indor units comunicate with the outdoor with only 3 wires , phase, neutral and signal . If you measured in the signal wire then you may have some unstable readings of frequency . Anyway for more real results you have to measure the voltage with an portable oschiloscope if someone own some such instrument .

[texanul]

Try to get out one unit at time and run with the remaining units . See if works . If not take out another unit and run again . Finally when you find the damaged one the rest of the sistem should run fine . Taking out i mean taking out of network no`t piping sistem .

[AbiBrl]

HI everyone, All these days the problem was with the setting. There is something optional setting in the machine which was ON. Basically the setting was for receiving the signal from the roon thermostat. Since we did not connected any the machine did not sense in any temperature and was running in fan mode. Anyway thank you all for your support and ideas. Have a nice day

[Brian_UK]

Thank you AbiBri for the update, glad that you have resolved the problem.