Carrier 19QA - Manual (Page 15)

MAINTENANCE
Periodic maintenance is necessary to keep all compo­
nents functioning as designed. A maintenance log is rec­
ommended to ensure a proper maintenance schedule is
followed.
Maintaining the Pump — Clean lubricating oil is es­
sential to maintaining the required vacuum capabilities. If
the oil is diluted with refrigerant, it will not be able to ob­
tain a 29 in. Hg (25 mm Hg absolute) rating. Refer to
Table 5 for additional information.
Change the oil in the pump and separator before each
use. Both the pump and the oil separator use 16 oz. of
300 SSU oil at 100 F (38 C). The pump and oil separator
have drain ports for oil removal. The drain port for the oil
separator is located on top of the separator. The drain port
for the pump is located on the bottom of the pump. Drain
the oil from the separator by using the pump to pressurize
the oil separator with air.
Install a 3-ft refrigerant hose on the discharge connection
of the oil separator and close the refrigerant hose valves.
Open the pump’s suction and discharge service valves. Turn
the pump on and let it run until it shuts down due to the
high pressure cutout at 10 psig (69 kPa). Use this pressure
to drain the oil from the separator. When this is complete,
drain the oil from the pump. Use the oil drain fittings and a
hand pump to add new oil to the pump and separator.
Check pump’s vacuum capability once per year. Place a
test gage capable of reading 29 in. Hg (25 mm Hg) on the
suction service valve. Open the pump suction and dis­
charge service valves. Start the pump and measure the vac­
uum. If the pump does not achieve the proper vacuum, a
new valve plate assembly should be installed. Installation
instructions are provided with the new valve plate assembly
from the manufacturer.
Pump Coupling — The aluminum, self-aligning cou­
pling should be inspected for wear at least once a year or as
required based on usage. The pump half of the coupling is
secured on a tapered shaft with a key and lock nut. The mo­
tor half of the coupling is secured on a straight shaft with a
key and set screw. The rubber insert, found between each
coupling half, should be inspected for damage and replaced
as needed. Remove the coupling guard and pump to access
the pump coupling. Leave the base brackets in place.
High-Pressure Cutout Switches — Check the pres­
sure cutout setting for the pump and heater pressure switches
once per year. Each switch should shut the pump off at
10 psig (69 kPa). To check the pump and heater switches,
disconnect the capillary tube and use a regulated pressure
source. Verify with an ohmmeter that the switch opened at
10 psig (69 kPa).
Refrigerant Storage Tank — The refrigerant stor­
age tank contains a cleanout cover. Remove the cover to
clean the tank when required. Use a clean cloth to wipe the
inside of the tank. Reinstall cleanout cover.
Refrigerant Hoses — Each refrigerant hose has a fac­
tory supplied, field installed ball valve and coupler assem­
bly at each end. These couplers contain a rubber seat that
must be replaced periodically. Inspect the rubber seats be­
fore each use. Replace the seats if they appear to be dam­
aged. See Fig. 15.
Periodically check refrigerant hoses for cuts or abrasions
that may allow refrigerant to leak into the atmosphere.
SIDE VIEW END VIEW
Fig. 15 — Refrigerant Hose Seats
15