Heavy Duty Balanced Opposed Compressors

FOR MODELS: JG AND JGA SECTION 5 - MAINTENANCE
Valves
Valves - Removal
1. Slightly loosen all of the bolts on each valve cap. With all the bolts loose, the cap
should stay in its original position. If it pushes out on its own accord-stop! Take
steps to completely vent the cylinder. See Caution above. A typical valve
assembly is shown in Figure 5-18: on Page 5-33.
2. After all the above safety checks, remove the valve cap bolts. A pair of prybars
(or screwdrivers), one on each side of the cap, will help pry it loose. With the
retainer still in place, screw a valve tool over the valve center bolt. See Figure 7-
1: on page 7-3. Now the valve and retainer can be pulled out together. For cylinder
class 1-3/4JG-FS-HE and 2-1/2JG-FS-HE tandem cylinders, the suction and
discharge piping and cylinder head must be removed to gain access to the concentric
valve. A concentric valve combines the suction and discharge valves in
one assembly. See Caution at “Piston and Rod - Removal” on page 5-18.
3. In most cases the flat metal gasket will remain in the pocket. It is difficult to see.
A flashlight and a small mirror on an adjustable rod are the best tools to see the
gasket clearly. On cylinders with horizontal valves, the gasket may fall into the
gas passage. A small magnet on a flexible extension rod will help fish it out. This
gasket should be replaced after several uses.
Valves - Maintenance
!
CAUTION
BEFORE ATTEMPTING TO REMOVE ANY VALVE CAP, BE
CERTAIN THAT ALL PRESSURE HAS BEEN VENTED FROM
THE COMPRESSOR CYLINDER. THE PRESSURE MUST BE
COMPLETELY VENTED FROM BOTH THE SUCTION AND
DISCHARGE PASSAGES OF THE CYLINDER. SEE FIGURE 1-
3: ON PAGE 1-3 FOR LOCATION OF IMPORTANT SAFETY
INFORMATION PLATES.
Ariel uses valves manufactured by Hoerbiger Corporation. Before servicing any valve refer
to the correct valve assembly drawing and parts list and Hoerbiger's literature in the Parts
Book. On the valve assembly drawing you will notice that valves have different springing for
different pressure levels. The cylinder cover sheet in the Parts Book lists the valve originally
supplied with each cylinder. If different operating pressures are encountered, then different
springs may be required.
The suction valve must be selected on the basis of operating suction pressure and the discharge
valve for operating discharge pressure. Proper valve spring selection is also based
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