Robinair 75700 Coolant Exchanger - Manual (Page 6)

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© 2003 SPX Corporation
Relieve Cooling System Pressure
On some systems it is necessary to allow the cooling
system to cool before servicing the vehicle. On
vehicles that have a radiator cap, it is possible to relieve
pressure by drawing a vacuum on the overflow port.
System Inspection
Before starting the service procedure, verify :
• the 75700 unit is connected to a supply tank
holding the correct amount and type of new
coolant for the vehicle being serviced.
• the waste coolant tank has enough capacity to
exchange the desired amount of coolant.
Note: Running the unit with a full waste tank will
degrade the performance of the unit.
• the vehicle ignition is in the OFF position.
• valves 1 and 2 on the 75700 unit are OFF.
• the valve on the black hose is open. See Figure 3.
• the filter screen on the clear hose is clean.
Relieve Pressure on a Hot System
that has a Radiator Cap :
1. Remove the vehicle’s overflow tank hose from
the coolant overflow barb on the radiator neck.
2. Two sizes of siphon tubes have been included with
the 75700 unit. See Fig. 4. Select the siphon tube
which most closely matches the size of the coolant
overflow barb on the vehicle’s radiator neck.
3. Slide the siphon tube onto the coolant overflow
barb on the radiator neck.
4. Connect the coupler end of the siphon tube to the
clear hose from the 75700 unit. See Figure 5.
5. Turn both valves on the unit to VACUUM. As the
valve in the radiator cap releases pressure,
coolant may be seen in the siphon tube.
6. After pressure is relieved, turn both valves OFF.
Figure 3
l l l l l
Figure 4
Figure 5
Black Hose
(new coolant)
Valve in
OPEN
position.
Siphon Tubes
Siphon tube
assembled
between clear
hose and
overflow barb
on radiator.
WARNING: Cooling systems that are hot,
are under pressure. Working on a hot cooling
system without first relieving the pressure
will result in serious personal injury.