Automatic Judgement System For Refrigerant Amount - Hitachi FSXN Series Service Manual

7 Test run
b. Heating operation (this is applicable when the outdoor temperature is higher than 0 °C).
No. Check item
Are oE1 and oE2 (opening of the outdoor unit
1 expansion valves) abnormally low or high when
TdSH is between 15 and 45 degrees?
Is Pd between "1.6" and "3.5"?
2
(Pd is high when the indoor temperature is high).
3 Is Ps between "0.2" and "1.1"?
Is the difference in temperature between indoor
units* more than 10 °C when iE (indoor unit
expansion valve) is "100?
* The difference in temperature between indoor units
means the following:
4
b3 (discharge air temperature) -b2 (air inlet
temperature) indicated on the remote control by the
check mode.
However, this is only applicable when b2 (Air inlet
temperature) -b1 (setting temperature) is higher
than 3 °C.
N O T E
Underlined indicates checking items and the mark " " indicates checking data.

7.2.6 Automatic judgement system for refrigerant amount

< Before refrigerant amount judgement >
(1) Check the indoor and outdoor temperature in the picture.
(2) Calculate the amount of refrigerant for the length of the pipe and add it.
Refrigerant Amount Judgement
43
10
0 10 20
Indoor Air Temperature [°C]
143
SMGB0065 rev. 1 - 12/2010
32
Standard Causes
• Low: excessive refrigerant.
—
• High: insufficient refrigerant.
• Low: solenoid valve SVA leak .
— • High: excessive pressure loss
in the gas pipe.
• Low: outdoor unit short-circuit.
• low/high: outdoor unit fan motor
— failure, fan module failure or
outdoor unit ambient
temperature thermistor failure.
• Failure such as PCB, wiring,
indoor unit expansion valve and
coil
• Excessive pressure loss in the
pipe.
• Thermistor failure for air
—
discharge
Result
7