Komatsu GD555-5 Operation & Maintenance Manual page 276

MAINTENANCE
SERVICE PROCEDURE
CHECK QUANTITY OF REFRIGERANT
WARNING
If the refrigerant used in the air conditioner gets into your eyes or on your hands, it may cause loss of sight or frostbite. Do not
touch the refrigerant. Never loosen any part of the refrigerant circuit.
Do not bring any flame close to any point where the refrigerant gas is leaking.
If the cooling effect is poor, the refrigerant (gas) level may be low.
If this is the case, check the sight gauge of the receiver dryer under
the right side of the cab.
REMARK
Run the engine at idle, and if bubbles appear in the sight glass
when the air conditioner is set to cooling, the refrigerant level is low,
so please contact your Komatsu distributor to have it refilled.
CHECK TENSION OF AIR CONDITIONER COMPRESSOR BELT
If the belt is loose, it will slip and it will become impossible to carry
out cooling properly.
From time to time, check the belt tension. Press the belt at a point
(A) midway between the drive pulley and compressor pulley and
check that the deflection is 17 to 19 mm (0.67 to 0.75 in) (new belt:
15 to 16 mm (0.59 to 0.63 in)) when pushed with a finger force of
approximately 98 N (10 kg).
When the belt is new, it is particularly likely to stretch at the initial
stages, so it must be adjusted again after 2 to 3 days.
Check each pulley for damage, wear of the V-groove, and wear of the V-belt. Be particularly careful to check that
the V-belt does not contact the bottom of the V-groove.
If the belt is stretched and there is no allowance for adjustment, or it is cut or cracked, replace it with a new belt.
When adjusting the V-belt, do not push the compressor directly with a bar; use a wrench.
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