VRF Set Free Hitachi - RAS24FS5

[Rafael Brazil]

I have facing a problem on VRF Set Free Hitachi RAS24FS5. The ISPM board (inverter - compressor) was damaged and the entire system has dropped. As I do not have a spare board to carry out the change I would like to know whether I have an option to run the system without the compressor inverter. My system has 4 compressors, being 1 inverter and 3 normals.
In the meantime I will try to find a new ISPM board.
We are now in the summer and I need the system running temporarily without the ISPM board.
Thanks in advance for some help.
Rafael (Brazil)

[install monkey]

does the inverter board have the flashing comms ligt?- on ras 8,10 units we disconnect the lead to the inverter compressor and it will not alarm and only give 50% capacity,if the inv pcb is damaged you may not be able to disable the inv compressorFailure of Inverter Compressor
a. Contents of Operation
(Applied Models: RAS-8FSG(3), 10FSG(3), 16FSG(3), 20FSG(3), 24FSG1(5), 30FSG1(5) /
RAS-8FXG(3), 10FXG(3))
* This operation is an emergency operation by a constant compressor, when the inverter
compressor is failed.
* By turning ON “#1” of DSW7 on PCB1 and “#1” of DSW1 on PCB3, emergency operation is
started. (In Case of 5 to 20HP)
* By turning ON “#6” of DSW4 on PCB1 and “#1” of DSW1 on ISPM, emergency operation is
started. (In Case of 24 and 30HP)
* Control of the emergency operation is same with normal control except the inverter compressor
stoppage.
b. Operating Condition
The constant speed compressor is forced to be stopped for compressor protection under the
condition below.
Total Capacity of Thermo-ON indoor units < 50% of Outdoor Unit Capacity
In case of the above condition, the compressor is operated and stopped repeatedly, and it may
cause the compressor failure. Therefore, the compressor is forced to be stopped to protect it.
NOTE:
If the printed circuit board for inverter (PCB3) is damaged, this is not available

[Rafael Brazil]

Hi, Monkey!
Thanks for the reply.
I have tried what you suggested me to do but the system is still stopped. Actually, if I try to turn on any indoor unit on COOL option I get the error message 04 (means no communication with ISPM or ISPM trouble) on PCB1 board.
The system has two ISPM boards: one for the compressor and one for the fan. On both I have positioned DSW #1# at ON.
The comm LED is lighted on ISPM 1 (compressor) but it is not lighted on ISPM 2 (fan).
If I run tests, by positioning DSW8 (PCB1) #2# at ON, the system works for a while with normal compressors and then stops again. In this case, it does`t matter if using only one normal compressor or three.
Do you think I have any other option to temporarily run the system?

Thanks again.
Rafael

[install monkey]

sorry- i dont think so,the system has to communicate between pcb to establish operation,is there another system you can borrow a pcb?-have you checked all the glass fuses are ok,as hitatchi are renown for hiding inline fuse carriers-normally about 5 glass fuses on an outdoor unit

[Rafael Brazil]

I changed the main PCB board by a new one. However, the problem is the same. I also borrowed ISPM boards (1 and 2) from a local supplier, but they don`t look like brand new boards.
As I mentioned, if I run normal compressors by Test Operation (DSW8 #2# ON) the system run for a while. What I need is just keep normal compressors (1, 2 or 3) running. I can fix the same temperature for all indoor units.

[Rafael Brazil]

Does anybody knows how to keep the normal compressors running at a pre-fixed temperature on indoor units?

This way I can keep inverter compressor stopped.

Thanks.

[Air Bear]

There is no way the system will run without the ISPM, It must have comms to the ISPM otherwise will fault on 04.
Sorry

[Mrdaikin]

If you have a PC-ART controller I think if you hold down TEMP. V for 3 seconds this may set emergency mode?? Should display EMG on controller.

[assailant]

If you have a PC-ART controller I think if you hold down TEMP. V for 3 seconds this may set emergency mode?? Should display EMG on controller.

Thats a new one.. i havent heard that about the PC-ART. ill have to try it.
usually CHECK + MODE for 5s will give you test run mode, but that wont get around the ISPM, only the thermistors etc