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Beware of rotating evaporator fan when conducting following test.
4.1
MAINTENANCE SCHEDULE
UNIT
ON
OFF
a. Daily Maintenance
X
Pre-trip inspection --- after starting
X
Check tension and condition of V-belt(s)
b. Weekly Inspection and Maintenance
X
Perform daily inspection
X
Check condenser, evaporator coils and air filters
X
Check refrigerant hoses and compressor shaft seal for leaks
X
Feel filter-drier for excessive temperature drop across drier.
c. Monthly Inspection and Maintenance
X
Perform weekly inspection and maintenance
X
Clean evaporator drain pan and hose(s)
X
Check wire harness for chafing and loose terminals
X
Check fan motor bearings
X
Check compressor mounting bolts for tightness
X
Check fan motor brushes
4.2
SUCTION AND DISCHARGE SERVICE
VALVES
The suction and discharge service valves used on
the compressor are equipped with mating flanges
for connection to flanges on the compressor.
These valves are provided with a double seat and
a gauge connection, which allows servicing of the
compressor and refrigerant lines.
Turning the valve stem counterclockwise (all the
way out) will backseat the valve to open the suction
or discharge line to the compressor and close off
the gauge connection. In normal operation, the
valve is backseated to allow full flow through the
valve. The valve should always be backseated
when connecting the service manifold gauge lines
to the gauge ports.
Turning the valve stem clockwise (all the way
forward) will frontseat the valve to close off the
suction or discharge line to isolate the compressor
and open the gauge connection.
To measure suction or discharge pressure,
midseat the valve by opening the valve clockwise
1/4 to 1/2 turn. With the valve stem midway
between frontseated and backseated positions,
SECTION 4
SERVICE
WARNING
OPERATION
OPERATION
the suction or discharge line is open to both the
compressor and the gauge connection.
To Discharge or
from Suction Line
Port to
Compressor
Service Valve
Frontseated
(clockwise)
Figure 4-1. Suction or Discharge Service Valve
4.3
INSTALLING MANIFOLD GAUGE SET
The manifold gauge set can be used to monitor
system operation pressure, add or remove
refrigerant, evacuate, and equalize the system.
The manifold gauge in Figure 4-2 shows hand
valves, gauges and refrigerant openings. When
the manifold hand valves are backseated (open),
the high and low side hoses are common with the
4-1
REFERENCE
REFERENCE
SECTION
2.1 and 2.2
and
None
4.1a
None
4.6
4.10
4.1b
None
Replace/Tighten
None
None
4.16
Valve Cap
Valve
Gauge
Stem
Connection
Service Valve
Backseated
(counterclockwise)
T-288
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