Komatsu 830E-AC Shop Manual page 696

Temperature During Precharge
Temperature variation can affect the precharge pres-
sure of an accumulator. As the temperature
increases, the pre-charge pressure increases. Con-
versely, decreasing temperature will decrease the
precharge pressure. In order to insure the accuracy
of the accumulator precharge pressure, the tempera-
ture variation must be accounted for. A temperature
variation factor is determined by the ambient temper-
ature encountered at the time when charging the
accumulator on a truck that has been shut down for
one hour. Refer to Table 2 for charging pressures in
different ambient operating conditions that the truck
is currently exposed to DURING the charging proce-
dure.
Example: Assuming the ambient temperature is 10°C
(50°F) charge the accumulator to 9294 kPa (1348
psi).
TABLE 1. Relationship Between Charging
Pressure and Ambient Temperature
Ambient
Temperature
-23°C (-10°F) and below
-17°C (0°F)
-12°C (10°F)
-7°C (20°F)
-1°C (30°F)
4°C (40°F)
10°C (50°F)
16°C (60°F)
21°C (70°F)
27°C (80°F)
32°C (90°F)
38°C (100°F)
43°C (110°F)
49°C (120°F)
NOTE: Pressures pressures below 8232 kPa (1194
psi) are not recommended. The low accumulator
pressure warning switch activates at 7584 ± 310 kPa
(1100 ± 45 psi).
L5-12
Charging Pressure
± 70 kPa (10 psi)
8232 kPa (1194 psi)
8412 kPa (1220 psi)
8584 kPa (1245 psi)
8763 kPa (1271 psi)
8943 kPa (1297 psi)
9122 kPa (1323 psi)
9294 kPa (1348 psi)
9473 kPa (1374 psi)
9653 kPa (1400 psi)
9832 kPa (1426 psi)
10011 kPa (1452 psi)
10184 kPa (1477 psi)
10363 kPa (1503 psi)
10542 kPa (1529 psi)
Steering Component Repair
ACCUMULATOR STORAGE
PROCEDURES
When storing an accumulator, pressurize the
accumulator to 690-827 kPa (100-120 psi). DO
NOT exceed 827 kPa (120 psi). Sudden loss of the
accumulator pressure can result in a projectile
hazard that can cause serious injury or death.
Only precharge the accumulators to operating
pressure while installed on the truck. DO NOT
handle the accumulator with a nitrogen pre-
charge greater than 827 kPa (120 psi).
Instructions For Storing Bladder Accumulators
1. If accumulator was just rebuilt, make sure there
is approximately 5% (of accumulator capacity)
of oil inside the accumulator before adding
nitrogen precharge pressure. Refer to Table 1
for oil lubrication amounts.
2. Refer to Accumulator Charging Procedure
instructions to charge accumulator with nitrogen
first to 172 kPa (25 psi), then up to 690 - 827
kPa (100 - 120 psi).
NOTE: Pressurizing the accumulator fully expands
the bladder and holds a film of oil against the inner
walls for lubrication and rust prevention.
3. The hydraulic port should always be covered
with a plastic plug (without threads) to prevent
contamination. DO NOT install a threaded
plug in the hydraulic port.
4. Only store the accumulator in an upright posi-
tion.
L05035