SANDPIPER GH2 - Manual (Page 3)

gh2dl1sm-REV0714 Model GH2 Page 3
move back and forth freely. This is most important when the gas supply is lubricated.
If a lubricator is used, oil accumulation will, over time, collect any debris from the com-
pressed gas. This can prevent the pump from operating properly.
Water in the compressed gas supply can create problems such as icing or
freezing of the exhaust gas causing the pump to cycle erratically, or stop operating.
This can be addressed by using a point of use dryer to supplement a plant’s gas drying
equipment. This device will remove excess water from the compressed gas supply and
alleviate the icing or freezing problem.
ESGDS: Externally Serviceable Gas Distribution System
Please refer to the exploded view drawing and parts list in the Service Manual
supplied with your pump. If you need replacement or additional copies, contact your
local Warren Rupp Distributor, or the Warren Rupp factory Literature Department. To
receive the correct manual, you must specify the MODEL and TYPE information found
on the name plate of the pump.
Main Natural Gas Valve
The main natural gas valve sleeve and spool set is located in the valve body mounted
on the pump with four hex head capscrews. The valve body assembly is removed from
the pump by removing these four hex head capscrews.
With the valve body assembly off the pump, access to the sleeve and spool set is
made by removing four hex head capscrews (each end) on the end caps of the valve
body assembly. With the end caps removed, slide the spool back and forth in the sleeve.
The spool is closely sized to the sleeve and must move freely to allow for proper pump
operation. An accumulation of oil, dirt or other contaminants from the pump’s gas sup-
ply, or from a failed diaphragm, may prevent the spool from moving freely. This can
cause the spool to stick in a position that prevents the pump from operating. If this is
the case, the sleeve and spool set should be removed from the valve body for cleaning
and further inspection.
Remove the spool from the sleeve. Using an arbor press or bench vise (with
an improvised mandrel), press the sleeve from the valve body. Take care not to
damage the sleeve. At this point, inspect the o-rings on the sleeve for nicks, tears or
abrasions. Damage of this sort could happen during assembly or servicing. A sheared
or cut o-ring can allow the pump’s compressed gas supply to leak or bypass within the
valve assembly, causing the pump to leak compressed gas from the pump exhaust
or not cycle properly. This is most noticeable at pump dead head or high discharge
pressure conditions. Replace any of these o-rings as required or set up a routine,
preventive maintenance schedule to do so on a regular basis. This practice should
include cleaning the spool and sleeve components with a safety solvent or equivalent,
inspecting for signs of wear or damage, and replacing worn components.
To re-install the sleeve and spool set, lightly lubricate the o-rings on the
sleeve with an o-ring assembly lubricant or lightweight oil (such as 10 wt. gas line
lubricant). Press the set into the valve body easily, without shearing the o-rings.
Re-install one end cap, gasket and bumper on the valve body. Using the arbor press or
bench vise that was used in disassembly, press the sleeve back into the valve body. You
may have to clean the surfaces of the valve body where the end caps mount. Material
may remain from the old gasket. Old material not cleaned from this area may cause air
leakage after reassembly. Take care that the bumper stays in place allowing the sleeve
to press in all the way. Reinstall the spool, the opposite end cap, gasket and bumper
on the valve body. After inspecting and cleaning the gasket surfaces on the valve body
and intermediate, reinstall the valve body on the pump using new gaskets. Tighten the
four hex head capscrews evenly and in an alternating cross pattern.
PILOT VALVE ACTUATOR SERVICING
The bushings for the pilot valve actuators are threaded into the intermedi-
ate bracket from the outside. The plunger may be removed for inspection or
replacement from the inside by removing the natural gas distribution valve body and
the pilot valve body from the pump. The plungers should be visible as you look into
the intermediate from the top. Depending on their position, you may find it necessary
to use a fine piece of wire to pull them out.
Under rare circumstances, it may become necessary to replace the o-ring seal. The
bushing can be pushed through the inner chamber by removing the outer chamber the
assembly to reach the bushing.
TROUBLE SHOOTING