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Function Tests
It’s a good idea to perform the following function tests to ensure the RHS780 is operating correctly
prior to using it to service an A/C system. These tests will also demonstrate some of the basic
operating functions.
The technical support group at RTI Technologies should be contacted if any problems or
questions arise during the following tests. Call 800-468-2321 (ext. 259) for assistance.
EVACUATE HOSES AND TEST VACUUM PROCESS:
1. The RHS780 should be set up and refrigerant transferred into the internal cylinder as described previously. The
tank of new refrigerant (with hose attached) should have been disconnected from the RHS780 and the plastic cap
installed on the port.
2. Plug in power cord and press top of power selector switch. The display will show
WEIGHT = XX.X LB -
AUTOMATIC?
3. Press
[
_
_
_
_
]
key two times. The display will show
WEIGHT = XX.X LB - VACUUM?
.
4. Press
[ENTER]
key. The display will show
ENTER VACUUM - TIME XX MIN.
5. Press the
[
<<<<
]
key one time to move the blinking cursor one position to the right. Press
[
_
_
_
_
]
key two times until the
display shows
ENTER VACUUM - TIME 02 MIN
.
6. Press
[ENTER]
key. The display will show
PERFORM LEAK TEST? Y/N
. Press
[
<<<<
]
key as required until
N
is
flashing to indicate that a leak test is not desired.
7. Press
[ENTER]
key. The display will show
ADD OIL? Y/N
. Press
[
<<<<
]
key as required until
N
is flashing to indicate
that adding oil is not desired.
8. Press
[ENTER]
key. The display will show
START?
.
9. Press
[ENTER]
key. The display will show
TIME LEFT = XX MIN - PUMP ON
. The vacuum pump will start
running. Watch the High and Low pressure gauges to verify that the pressure drops into a vacuum as the red and
blue hoses are evacuated. The display will show
PUMP OFF XX MIN - CONTINUE?
at the end of two minutes.
10. Press
[ENTER]
key. The display will show
WEIGHT = XX.X LB - AUTOMATIC?
. Continue to next test.
FILL HOSES AND TEST CHARGE PROCESS:
1. Press
[
_
_
_
_
]
key three times. The display will show
WEIGHT = XX.X LB - CHARGE?
.
2. Press
[ENTER]
key. The display will show
ENTER CHARGE - AMOUNT = XX.X LB
.
3. Press the
[
<<<<
]
key one time to move the blinking cursor to the right one position. Press the
[
_
_
_
_
]
key one time until
the display shows
ENTER CHARGE - AMOUNT = 01.0 LB
.
4. Press
[ENTER]
key. The display will show
CHECK HIGH-LOW - CHARGE SWITCH
. This message is asking if
you want to charge through the red high side hose or the blue low side hose. For test purposes we will charge
through one and then the other to fill both hoses with refrigerant. The High-Low Charge Switch is on the left side
of the RHS780 above the port where the yellow hose was connected during the filling of the internal cylinder. Press
the top of this switch.
5. Press
[ENTER]
key. Refrigerant will fill the blue low side hose. The low pressure gauge will show the pressure
rise from a vacuum to the pressure of the refrigerant charged into the hose. Next press the bottom of the High-Low
Charge Switch. Refrigerant will fill the red high side hose. The high pressure gauge will show the pressure rise
from a vacuum to the pressure of the refrigerant charged into the hose. The display will show
WEIGHT = 01.0 LB -
CHARGING
. The amount may or may not change as the two hoses are filled.
6. Press
[RESET]
key. The display will show
WEIGHT = XX.X LB - AUTOMATIC?
Continue to next test.
