15 Maintaining a Valve
To Replace a Rotary Valve in the Valve Box
Maintaining Your GC 233
To Replace a Rotary Valve in the Valve Box
Do not install a liquid sampling valve (LSV) in the valve box if you plan to heat the box above
75 °C. Heating an LSV over 75 °C can cause a leak and subsequent explosion. LSVs should
be mounted in the side location to avoid potential explosions.
1 Gather the following:
• Replacement valve, see “Consumables and Parts for Valves” on page 228.
• T-10 Torx screwdriver
• 1/4-inch wrench
• Needle-nosed pliers
• Vacuum
2 Place GC in maintenance mode: Maintenance > Instrument > Perform Maintenance >
Maintenance Mode > Start Maintenance. Wait for the GC to become ready.
The oven, inlet, detector, and valve box may be very hot.
Sample and/or harmful gases may be present. Refer to your company’s standard operating
procedures for purging the chemicals from the sample line.
3 Set all valves to Off.
4 Leave on the GC and valve actuator air.
5 Turn off the carrier gas and sample line flows and relieve any back pressure to the valve.
The valve box insulation is made of refractory ceramic fibers (RCFs). To avoid inhaling RCF
particles, we recommend these safety procedures:
•Ventilate your work area
• Wear long sleeves, gloves, safety glasses, and a disposable dust/mist respirator
• Dispose of insulation in a sealed plastic bag
• Vacuum any residual particles and discard
• Wash your hands with mild soap and cold water after handling RCFs.
6 Remove the upper valve box. See “To Remove the Upper Valve Box” on page 236.
Vacuum any RCF insulation particulates from the valve box area.
7 Note the tubing connections to the existing valve and label if desired.
8 Disconnect the existing valve fittings.
9 Remove the two T-10 Torx screws attaching the valve to the valve box, then remove the
valve from the valve box.
10 Place the new valve in the valve box. The gap in the index ring on top of a 6-port valve
points toward the back of the GC if installed correctly. This is the On position. Install and
tighten the two screws with a screwdriver.
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