Hitachi FSG Series, Technical Catalogue

Page: 386 / 424

17
/10
TEST RUN
17.5 CHECKING OF REFRIGERANT QUANTITY
17.5.1 FSG SYSTEM
An excess or deficiency of the refrigerant can be checked by
using data from 7-segments display check mode. This
checking procedure, as follows, is useful at test run or
maintenance.
n
Before Checking:
1. Operate all the indoor units at the “TEST RUN” mode and
operate all the indoor units at the “HIGH” speed.
2. Check the following items to ensure that the refrigeration
cycle is stable.
a) The continuous operation is for more than 20 min.
b) Td · SH is 20 to 40 degree in Celsius.
c) Ps is 2.0 to 5.0 kgf/cm
2
G.
d) Pd is 14 to 22.5 kgf/cm
2
G.
[Td · SH: Discharge Gas Temperature Superheat]
[Ps: Suction Pressure] [Pd: Discharge Pressure]
3. Collect the checking data by the 7-segment display check
mode.
Refer to “Table of Test Run maintenance record" (page
17/7).
4. Perform checking as the following procedures.
Applicable Operating Conditions of Air Temperature for
Checking:
[Cooling] Room Air Temperature:
20~30°C (DB)
Outdoor Air Temperature:
15 ~ 40°C (DB)
[Heating] Room Air Temperature:
20~30°C (DB)
Outdoor Air Temperature:
0~15°C (DB)
n
Checking Procedures:
Cooling Operation
1. Calculate iE (Indoor Unit Expansion Valve Opening) with
the conversion value (
É
) show below.
2. Sum up the converted values of iE.
3. Compare the total of iE with the normal value.
Normal Value: Outdoor Unit Capacity (HP) X 6 to
Outdoor Unit Capacity (HP) X 27
Tendency: In the case that the room air
temperature is high within the above
normal value, the value of iE will be
big.
Judgement: Total of iE>Normal Value
··· This means insufficient refrigerant
Total of iE>Normal Value
··· This means excessive refrigerant.
Heating Operation
1. Detect oE1 (Outdoor Unit Expansion Valve Opening).
2. Compare oE1 with the normal value
Normal Value: 20 to 75 (For details, refer to the next
page)
Tendency: When oE1 is within the above range
and
1) In the case that the room air
temperature is high, the value of
oE1 will be small.
2) In the case that the outdoor air
temperature is high, the value of
oE1 will be big.
Judgement: oE1>Normal Value
··· This means insufficient refrigerant.
oE1>Normal Value
··· This means excessive refrigerant.
É
Conversion Value at Cooling
Indoor Unit Capacity Indication at Check Mode
0.8 to 2.0 06~16
2.5 to 4.0 18~32
more than 5.0 40~48
(1)0
£
iE < 50%
1) 0.8 to 2HP: 1.0 x iE
2) 2.5 and 4HP: 0.7 x iE
3) 5HP: 0.7 x iE
(2)50%
£
iE < 100%
1) 0.8 to 2HP: 1.0x iE
2) 2.5 and 4HP: 2 x iE-60
3) 5HP: 2.7 x iE-100