Service; Section Layout; Service Valves; Manifold Gage Set - Carrier 69NT40-489-100 Series Operation And Service Manual

To avoid damage to the earth's ozone layer, use a refrigerant recovery system whenever removing refriger-
ant. When working with refrigerants you must comply with all local government environmental laws. In the
U.S.A., refer to EPA section 608.
DANGER
HAZARDOUS ATMOSPHERE INSIDE.
LOW OXYGEN INSIDE CONTAINER CAN
CAUSE DEATH.
Performing service on, or entering a CA
equipped unit can be extremely dangerous.
Refer to the Safety section of this manual
before servicing or entering the container.
WARNING
Never use air for leak testing. It has been de-
termined that pressurized, mixtures of re-
frigerant and air can undergo combustion
when exposed to an ignition source.

6.1 SECTION LAYOUT

Service procedures are provided herein beginning with
refrigeration system service, then refrigeration system
component service, electrical system service and
general service. Refer to the Table of Contents to locate
specific topics.

6.2 SERVICE VALVES

The compressor suction, compressor discharge and
liquid line service valves (see Figure 22) are provided
with a double seat and a gauge connection which enable
servicing of the compressor and refrigerant lines.
Turning the valve stem clockwise (all the way forward)
will frontseat the valve to close off the suction, discharge
or liquid line and open the gauge port to the compressor
or low side. Turning the stem counterclockwise (all the
way out) will backseat the valve to open the connections
and close off the port.
With the valve stem midway between frontseat and
backseat, the lines are open to both the connections and
the gauge connection.
For example, the valve stem is first fully backseated
when connecting a manifold gauge to measure
pressure. Then, the valve is opened 1/4 to 1/2 turn to
measure the pressure.
SECTION 6

SERVICE

NOTE
1
VALVE
FRONTSEATED
(Clockwise)
1. Suction, Discharge or
Liquid Line
Connection
2. Service Port

Figure 22. Service Valve

SUCTION
PRESSURE
GAUGE
OPENED (Backseated )
HAND VALVE
A. CONNECTION TO LOW SIDE OF SYSTEM
B. CONNECTION TO EITHER:
REFRIGERANT CYLINDER OR
OIL CONTAINER
C. CONNECTION TO HIGH SIDE OF SYSTEM
Figure 23. Manifold Gauge Set
6.3. MANIFOLD GAUGE SET
The manifold gauge set (see Figure 23) is used to
determine system operating pressure, add refrigerant
charge, and to equalize or evacuate the system.
When the suction pressure hand valve is frontseated
(turned all the way in), the suction (low) pressure can be
checked. When the discharge pressure hand valve is
frontseated, the discharge (high) pressure can be
checked. When both valves are open (turned
counter-clockwise all the way out), high pressure vapor
will flow into the low side. When the suction pressure
valve is open and the discharge pressure valve shut, the
system can be charged. Oil can also be added to the
system.
A R-134a manifold gauge/hose set with self-sealing
hoses (see Figure 24, page 58) is required for service of
the models covered within this manual. The manifold
57
2
6
VALVE
BACKSEATED
(Counterclockwise)
3. Stem Cap
4. Valve stem
5. Compressor Or Filter
Drier Inlet Connection
DISCHARGE
PRESSURE
GAUGE
B C
A
CLOSED (Frontseated)
HAND VALVE
4
5
T-305