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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.
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
temperature recorder 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 6-1) 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.
1
VALVE
FRONTSEATED
(Clockwise)
1. Suction, Discharge or
Liquid Line
Connection
2. Service Port
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service,
electrical
system
2
5
VALVE
BACKSEATED
(Counterclockwise)
3. Stem Cap
4. Valve stem
5. Compressor Or Filter
Drier Inlet Connection
Figure 6-1 Service Valve
search engine
SECTION 6
SERVICE
NOTE
SUCTION
PRESSURE
GAUGE
OPENED (Backseated )
service,
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 6-2 Manifold Gauge Set
6.3. MANIFOLD GAUGE SET
The manifold gauge set (see Figure 6-2) 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.
3
A R-134a manifold gauge/hose set with self-sealing
hoses (see Figure 6-3) is required for service of the
models covered within this manual. The manifold
gauge/hose set is available from Carrier Transicold.
(Carrier Transicold P/N 07-00294-00, which includes
items 1 through 6, Figure 6-3.) To perform service using
the manifold gage/hose set, do the following:
4
a. Preparing Manifold Gauge/Hose Set For Use
1. If the manifold gauge/hose set is new or was
exposed to the atmosphere it will need to be eva-
cuated to remove contaminants and air as follows:
2. Back seat (turn counterclockwise )both field service
couplings (see Figure 6-3) and midseat both hand
valves.
3. Connect the yellow hose to a vacuum pump and re-
frigerant 134a cylinder.
4. Evacuate to 10 inches of vacuum and then charge
with R-134a to a slightly positive pressure of 0.1 kg/
cm@ (1.0 psig).
6-1
DISCHARGE
PRESSURE
GAUGE
B
C
A
CLOSED (Frontseated)
HAND VALVE
T-296
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