Hitachi

[ubbe]

Hi,
I have a problem with a Hitachi multizone unit:
RAM65QH5 (inverter) with three indoor units RAK18NH5

The unit do not give correct cooling capacity the different between inlet temp and outlet temp. on the indoor units is: in 22°C out 17,5°C. The set temp is 16°C. With that different between indoor and set temp. shall the speed on the unit be around 4000 rpm but it just give 2000 rpm. I have try to replace the outdoor unit, and fill it up with correct amount refrigerant. But nothing of this have helped.

Any idés?

[chilly]

If there is a fault the led on both indoor and outdoor unit should flash in a certain sequance.

The electric cover on outdoor unit has diagnosis chart to help determine the fault.

If you are not getting a fault led then i would look at the cappacity / load of the room and compare to see if the indoor unit is too small for the job.

Try it in heating mode on full for 20 mins, What are the results?

Charge is very critical so did you weigh the gas..

Also are all indoor units doing the same or is it just on or two?

How many compressors? one or two, Its been a while since i looked at the multizone.

Good luck

[ubbe]

Hi chilly,
Thanks for your answer. There is just one compressor and all indoor units are the doing the same. There is no leds falshing. Anyway I will go to the site this week and recharge the unit this time by weight.

I have to succed the owner is not so happy.

Thank You

[DEVIL]

how meny indors dose the unit have, it migth be that the total indoor capacity is grater then the outdor , at list at DAIKIN this is posible , and if u have started all the indors, the outdor can't get all the indoors covered

[frank]

It's got to beg the question - is it sized correctly for the indoor load?

The system appears to be OK with 54000btu indoor units coupled to 65000btu outdoor unit but the small dt on the indoor leads me to think that the indoor load is too high.

[mgtet]

I used to work for one of hitachi's main distributors and i was told a few years ago that although the controller could be set at 17 the unit would only control to 19. This is on the older ras range of equipment though. I also agree with chilly, charge is critical on these units.

[ubbe]

Hello friends,
The problen is solved it was the charged of refrigerant.

Thanks for all your help

[chilly]

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