No peaks seen following injection - WKB75008

SYMPTOMS

• No peaks seen following injection
• Dual detectors in series collect signal; no peaks observed
• Cloudy liquid comes out of back of injection valve after injection
• Rebuilding RHEODYNE 7725i PERFORMANCE MAINTENANCE KIT [201000119] results in higher than expected back pressure
• Shavings/particulate observed when rebuilding injection valve

ENVIRONMENT

• 1515 Isocratic HPLC Pump

CAUSE

Worn injection valve

FIX or WORKAROUND

1. Replace Rheodyne Inject Vlv, 7725i, spare [WAT055840].
   1. Loosen the two set screws on the valve handle, and then remove the handle.
   2. Loosen the two captive Phillips screws that secure the mounting plate to the 1515 pump.
   3. Label if necessary and disconnect tubing fittings on the injection valve.
   4. Remove the valve from the mounting plate by removing the two screws.
   5. Install the new valve on the mounting plate.
   6. Install a new sample loop on the new injection valve.
   7. Install tubing fittings to the corresponding ports on the new injection valve.
   8. Reinstall the mounting plate to the 1515 pump using the two captive Phillips screws.
   9. Attach the valve handle to the valve and tighten the two set screws.

ADDITIONAL INFORMATION

Find the hex wrench size for the set screws in the documentation included with the PM kit (201000119).