4-9
62--611XX--20 (03/04)
4.4.3
Alternator V-belt
a.
Make
sure
negative
battery
terminal
is
disconnected.
b.
Tension is done by rotation of alternator around its
pivot.
4.4.4
Water pump belt tensioner
Water pump belt is driven by the diesel engine
crankshaft pulley. The automatic belt tensioner ensures
the correct tension.
To change the water pump belt, proceed as follows:
a.
To compress the tensioner spring, place a threaded
bolt or rod into hole and turn clockwise. This will draw
the spring up and slacken V-belt for easy removal.
b.
After replacing V-belt, remove the bolt to release the
spring to return the idler to it’s correct tension.
4.4.5
Standby motor - Compressor V-belt
Diesel engine - Compressor V-belt
a.
Tension is realized by moving idler pulley :
UPWARDS (Engine / Compressor)
DOWNWARDS (Standby / Compressor)
Depending on unit an adjusting screw easiest the
displacement of the pulley along the idler.
4.5
PUMPING THE UNIT DOWN OR REMOVING
THE REFRIGERANT CHARGE
NOTE
To avoid damage to the earth’s ozone layer, use a
refrigerant recovery system whenever removing
refrigerant.
a. Pumping the Unit Down
To service the filter-drier, expansion valve, quench
valve, CPR valve or evaporator coil, pump most of
refrigerant into condenser coil and receiver as follows :
1. Backseat suction and discharge service valve (turn
counterclockwise) to close off gauge connectionand
attach manifold gauges to valves.
2. Open valves two turns (clockwise). Purge gauge
line.
3. Close the receiver outlet (king) valve by turning
clockwise. Start unit and run in high speed cooling.
Place Run-stop switch in the STOP position when
unit reaches 0.1 kg/cm
@
(1 psig).
4. Frontseat (close) suction service valve and the
refrigerant will be trapped between the compressor
suction service valve and the manual shutoff (King)
valve.
5. Before opening up any part of the system, a slight
positive pressure should be indicated on the
pressure gauge.
6. When opening up the refrigerant system, certain
parts may frost. Allow the part to warm to ambient
temperature before dismantling. This avoids internal
condensation which puts moisture in the system.
7. Open (backseat) King valve and midseat suction
service valve.
8. Leak check connections with a leak detector.
9. Start the unit in cooling and check for
noncondensibles.
10.Check the refrigerant charge. (Refer to section
4.8.2)
NOTE
NOTE
Store the refrigerant charge in an evacuated
container if the system must be opened between the
compressor discharge valve and receiver.
Whenever the system is opened, it must be evacuated
and dehydrated. (Refer to section 4.7).
b. Removing the Refrigerant charge
Connect a refrigerant recovery system to the unit to
remove refrigerant charge. Refer to instructionprovided
by the manufacture of the refrigerant recovery system.
4.6
REFRIGERANT LEAK CHECKING
If system was opened and repairs completed, leak
check the unit.
a.
The recommended procedure for finding leaks in a
system is with a halide torch or electronic leak
detector. Testing joints with soapsuds is satisfactory
only for locating large leaks.
b.
If system is without refrigerant, charge system with
refrigerant to build up pressure between 2.1 to 3.5
kg/cm
@
(30 to 50 psig). Remove refrigerant cylinder
and leak check all connections.
NOTE
It must be emphasized that only the correct refrigerant
cylinder be connected to pressurize the system. Any
other gas or vapor will contaminate the system which
will require additional purging and evacuation of the
high side (discharge) of the system.