PM-80 TROUBLESHOOTING
This section contains troubleshooting tips specific to the PM-80 pump. For general troubleshooting see the main TROUBLESHOOTING page.
POWER WON'T TURN ON
- Check power connection.
- Check fuse and fuse type.
AUDIBLE NOISE
The drive train of the pump can be noisy when there is no load (no high pressure) on it. This audible cue is noticeable, for example, when the purge valve is open.
Drive-train noise during regular operation suggests that pressure is not being maintained. Observe the pressure display, and proceed to the Pressure Fluctuation section below if the difference between the highest and lowest pressures is greater than about 100 PSI.
NO SOLVENT FLOW
- Green Led's Don't Alternate
- Check FLOW RATE and FLOW RANGE controls. Are they set for valid, non-zero ranges (0.1-0.5 or 0.1-5 mL/min)?
- Is the START/STOP switch in the START position?
- Is the LOCAL/REMOTE switch in the LOCAL position?
- Is the high- or low-pressure LED on? If so, see the Pump Stops sections below.
- Is there an error message on the display? If so, call BAS.
- Green Led's Do Alternate
- Air in the pump. Check for loose connections on the inlet side of the pump. Purge with freshly degassed mobile phase as described in the STARTUP section.
- Mobile phase reservoir is empty. Purge with fresh mobile phase as described in the STARTUP section.
- Solvent-uptake frit is clogged. Remove temporarily and see if the pump now works.
PUMP STOPS: LOW-PRESSURE LIMIT
- The mobile-phase reservoir is empty. Make fresh mobile phase and purge as described in the STARTUP section.
- The MINIMUM potentiometer is set too high. Reset to 200 PSI or a reasonable value for your conditions.
- There's a leak in the system. Check all connections.
PUMP STOPS: HIGH-PRESSURE LIMIT
- The MAXIMUM potentiometer is set too low. Reset to 4000 PSI or a reasonable value (1000 PSI above your typical operating pressure) for your conditions.
- The injection valve is not fully in the inject or load position. Rotate it to one side.
- Have you changed to a more viscous mobile phase (e.g., one with methanol)?
- There's a clog in the flow path. It could be anywhere between the pump outlet and the detector. It may be the in-line solvent filter. Start opening fittings at the detector and work towards the pump. At some point the pressure will drop, pinpointing the location of the clog. (NOTE: There will be a normal drop in pressure when the column is removed.)
PRESSURE FLUCTUATIONS
- Purge the pump (see the STARTUP section) with freshly degassed mobile phase to remove air from the check valves. If performance improves, air bubbles were in the check valves. If the problem returns, degas the mobile phase more frequently, and check the connections to the inlet side of the pump, where air could be sucked in.
- Switch the inlet check valves between the two heads. If the pressure drop now occurs on the opposite pump head, it is associated with the inlet check valve on the head showing the problem. Clean or replace as described in the CHECK VALVES section.
- Switch the outlet check valves between the two heads. If the pressure drop now occurs on the opposite pump head, it is associated with the outlet check valve on the head that does not show a pressure drop. Clean or replace as described in the CHECK VALVES section.
- One or both pump heads may need an overhaul. See the PUMP HEADS section.
- One of the outlet lines from the pump to the pressure transducer may be clogged. Remove and examine. Replace as necessary.
FLUID LEAKS
- Fluid leaks from (or salt accumulates around) fittings. Leaks indicate that FITTINGS need to be tightened or replaced.
- Fluid leaks (or salt accumulates) around pump heads or from irrigation waste ports. This indicates that the plunger seals are worn and leaking. Replace the PLUNGER SEALS to prevent internal corrosion of the pump head.
- Fluid leaks (or salt accumulates) around the junction of the front and back halves of the pressure transducer. Replace the PRESSURE TRANSDUCER O-RINGS.
- Fluid leakage (or salt accumulation) at the prime/purge valve. Replace the PRIME/PURGE SEALS.
OVERHEATING
If the pump heads or cabinet feel warm, clean the FAN FILTER and check that the fan is operating.