HA-18
< PRECAUTION >
PRECAUTIONS
The lubricant contained inside the vacuum pump is not compatible
with the specified lubricant for HFC-134a (R-134a) A/C systems.
The vent side of the vacuum pump is exposed to atmospheric pres-
sure. So the vacuum pump lubricant may migrate out of the pump
into the service hose. This is possible when the pump is switched
OFF after evacuation (vacuuming) and hose is connected to it.
To prevent this migration, use a manual valve placed near the hose-
to-pump connection, as per the following.
• Vacuum pumps usually have a manual isolator valve as part of the
pump. Close this valve to isolate the service hose from the pump.
• Use a hose equipped with a manual shut-off valve near the pump
end for pumps without an isolator. Close the valve to isolate the
hose from the pump.
• Disconnect the hose from the pump if the hose has an automatic
shut-off valve. As long as the hose is connected, the valve is open
and lubricating oil may migrate.
Some one-way valves open when vacuum is applied and close
under no vacuum condition. Such valves may restrict the pump’s
ability to pull a deep vacuum and are not recommended.
MANIFOLD GAUGE SET
Be certain that the gauge face indicates HFC-134a or R-134a. Be
sure the gauge set has 1/2
″
-16 ACME threaded connections for ser-
vice hoses. Confirm the set has been used only with refrigerant
HFC-134a (R-134a) and specified lubricants.
SERVICE HOSES
Be certain that the service hoses display the markings described
(colored hose with black stripe). All hoses must equip positive shut-
off devices (either manual or automatic) near the end of the hoses
opposite to the manifold gauge.
SERVICE COUPLERS
RHA270DA
SHA533D
RHA272D