Ralston Instruments DPPV, Operation Manual

Page: 27 / 48

25
Troubleshooting
Dépannage ......................................27
Diagnóstico de problemas ...............29
故障排除 ..........................................31
Устранение неполадок ..................33
Solução de problemas .....................35
Diagnostica ......................................38
Fehlerbehebung ..............................40
EN
The pumping piston is difficult to pump
If the pumping piston is difficult to pump after years of use, then apply a
thin coat of graphite grease, such as Dow Corning
®
Moly-kote G-n Metal
Assembly Paste (or equivalent).
Pressure Mode
The pump will pump up, but pressure slowly decreases
If the pump will pump up, but pressure slowly decreases, then there is
an external leak. Follow these instructions to locate and repair the leak:
1. Connect the pump to a Device Under Test (DUT) with a Ralston
Quick-test™ hose.
2. Make sure the process connections are assembled wrench-tight.
3. Pressurize the Hand Pump.
4. Spray soapy water or leak detection fluid where leaks are suspected
or immerse the pump in water. Be careful not to immerse the pres-
sure gauge or calibrator.
5. Observe where bubbles are forming to determine where there is a leak.
6. Remove the leaking part and remove the cut or damaged O-ring.
7. Clean and lubricate the O-ring.
8. Replace the O-ring and reassemble.
Pumping Piston pushes out by itself and pressure
decreases
If the Pumping Piston pushes out by itself and pressure decreases,
then the Pressure Check Valve is not functioning properly. Follow these
instructions to replace the Pressure Check Valve (See Section A-A on
page 8 for reference):
1. Remove the Pumping Piston.
2. Remove the Pressure Check Valve.
3. Clean and lubricate the Pressure Check Valve.
4. Reinstall the Pressure Check Valve.
5. Reinstall the Pumping Piston.