Hitachi RAS 35yh5 and overload status problem

[igi]

Hello!
I have customer with a Hitachi split system RAS 35yh5. System is working normally for couple of years, but now not producing enough cooling. If room temperature is 28 degrees celsiou, air temperature from indoor unit is 21 degrees.
Indoor and outdoor unit are clean with fresh gas R410 in system.
I check outdoor electronic and there was “error” code on it (overload). LD301 and LD302 is on. There is no rule with lights, once burning LD301, other time LD302 and third both together. They start to burn in 5 minutes after start AC (when AC system approaching 800W, lights start burning and compressor speed fall down) Then whole system pulling approximate 650W. Lights burning all time.
I change both electronic plate in outdoor unit, but nothing change. Pressure on the service valve is too high (just small drop between system is off and working).

What can i do? Change compressor?
Is it possible that the problem comes from broken three-way valve or expansion valve?

Thank you

[lexmark42]

Hi igi,

I have a RAS-35YH5 running here as well which I use to heat a small room at my place. You need not be concerned with the diagnostic LEDs LD301, LD302 and LD303. They only indicate an error if they are blinking. If they are lit in a pattern this indicates only the status of the load control of the compressor.

However, the rated power consumption of the system is higher than the 650 W it falls back to. Normally as soon as the two LEDs start lighting up it should stabilize around the current power consumption, as this means that it keeps load at the current maximum.

What amound of R410A did you charge? How long is the piping? Could there be air or moisture in the system?

Can you check the color of the oil in the system?

Please let me know what you found out.

[install monkey]

sent u manual but its 14 meg so hope u get it

[lexmark42]

Just to mention it again - I also found that these units rarely consume their rated power.

I have found this to be different with many other inverter units which typically go to their maximum electrical load if there is a large temperature difference between setpoint and indoor ambient.

@Install monkey: Is this the hitachi way of doing it or just with my particular unit?

It would be nice if manufacturers would design control software more configurable. Sometimes you really need full power, but more often it is as good to limit compressor load in favour of a better COP.

[install monkey]

lexmark 42
states comp rating 800w
e mailed you the manual

Hello!
I have customer with a Hitachi split system RAS 35yh5. System is working normally for couple of years, but now not producing enough cooling. If room temperature is 28 degrees celsiou, air temperature from indoor unit is 21 degrees.
Indoor and outdoor unit are clean with fresh gas R410 in system.
I check outdoor electronic and there was “error” code on it (overload). LD301 and LD302 is on. There is no rule with lights, once burning LD301, other time LD302 and third both together. They start to burn in 5 minutes after start AC (when AC system approaching 800W, lights start burning and compressor speed fall down) Then whole system pulling approximate 650W. Lights burning all time.
I change both electronic plate in outdoor unit, but nothing change. Pressure on the service valve is too high (just small drop between system is off and working).

What can i do? Change compressor?
Is it possible that the problem comes from broken three-way valve or expansion valve?

Thank you

[lexmark42]

Hi install monkey,

you're right - that's the rating. Still, I've seen only few inverter units where the compressor rating is actually the upper limit of power consumption. The Panasonic, Toshiba, Fujitsu, and Mitsubishi units I know all go over 150% of compressor rating for a prolonged time. Admittedly these are all rotary compressor models.

I have not seen a lot of scrolls yet though. Is it common to run scrolls very cautiously in terms of performance?

Cheers,
-Dave

[install monkey]

as you say inverter splits, will ramp up to rated maximum fuse rating- as theres no surge/inertia on start up they can quite happily whistle away - until reaching setpoint target and then ramp right down to gurgle away at 1amp
-
Hi install monkey,

you're right - that's the rating. Still, I've seen only few inverter units where the compressor rating is actually the upper limit of power consumption. The Panasonic, Toshiba, Fujitsu, and Mitsubishi units I know all go over 150% of compressor rating for a prolonged time. Admittedly these are all rotary compressor models.

I have not seen a lot of scrolls yet though. Is it common to run scrolls very cautiously in terms of performance?

Cheers,
-Dave