Instruction Manual Model GX-86 Portable Four Gas Monitor Part Number: 71-0001RK Edition: Second Released: March 1998 RKI Instruments, Inc. • 33248 Central Ave.
Warranty RKI Instruments, Inc., warranties gas alarm equipment manufactured by RKI and sold by RKI to be free from defects in materials and workmanship for a period of one year from date of shipment from RKI Instruments, Inc. Any parts found defective within that period will be repaired or replaced, at our option, free of charge. This warranty does not apply to items that are subject to deterioration or consumption in normal service, and which must be cleaned, repaired, or replaced routinely.
Table of Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Components and Controls. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Case. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
iv Model GX-86 Operator’s Manual
Introduction The RKI Model GX-86 is a proven gas detection instrument, in use internationally for personal protection in a wide variety of industries.
Components and Controls This section describes the GX-86’s components and user controls. Case The GX-86 has a rigid plastic case that is durable and shock-resistant. The sensors are housed in a metal diffusion head at the bottom of the GX-86. The touch-pad control panel and display are located on the top. The carrying case has openings for the diffusion grill, buzzer, remote alarm, earphone jack, and control panel. The case includes a belt loop and shoulder strap loops.
CO and H2S sensors The CO and H2S sensors are physically identical, except for their external labels. The sensors are housed in a cylindrical plastic shell, with a bayonet-pin base for easy replacement. The perforations at the end of the shell allow atmosphere to diffuse into the sensor. The CO sensor also has a slip-on charcoal filter that covers the diffusion end. The filter eliminates interference from H2S.
Control Panel The control panel is at the top of the GX-86 for easy access when you carry the GX-86. The control panel contains the display, alarm lights, and buttons that control the many functions of the GX-86. The buttons are touch-pads to reduce the possibility of accidental activation or damage. Table 2: GX-86 Button Functions Button Function PEAK/AIR The PEAK/AIR button displays the highest reading for exposure to LEL, H2S, and CO, and the lowest reading for O2 exposure.
Operation Preparation Normally the GX-86 requires no preparation before use. To attach the sensor extender cable, see “Accessories” on page 14. Start-up 1. Press the ON button. The buzzer sounds a single tone, and the GX-86 displays the following: BATT. CK (MIN 2.3V) This message displays while the GX-86 is measuring the battery voltage. If the voltage is below the 2.3 volt minimum, the GX-86 cannot operate. BATT. (X.XV) This message displays the actual battery voltage; for example, (2.9V).
Normal Operation The GX-86 continuously monitors the atmosphere and displays the LEL, O2, H2S, and CO concentrations present. If the GX-86 is taken into a low-light environment, the display backlight automatically turns on. Displaying battery voltage Press the BATT button. A single tone sounds and the battery voltage displays. New alkaline batteries will register approximately 3.0V; freshly recharged Ni-Cd batteries will register approximately 2.7V. The minimum voltage required for the GX-86 is 2.3V.
Alarms This section describes the GX-86’s gas alarms. Table 3 lists the low and high alarm levels for each channel. Table 3: GX-86 Alarm Levels Channel Low High LEL 10% LEL 50% LEL O2 19.5% O2 23.5% O2 H2S 10.0 ppm 30.0 ppm CO 25 ppm 100 ppm Combustibles (%LEL) • If the target combustible gas exceeds the first alarm setting (10% LEL for most applications), a pulsed tone sounds and the COMB LED flashes.
Safety Self-Check The GX-86 continuously monitors itself for proper operation. If a malfunction occurs, a single steady “trouble” tone sounds, and one of the following messages display. Table 4: GX-86 Error Messages Display Description FAIL (CH4 O2 HS CO) Indicates sensor failure of one or more sensors (the failed sensor is displayed) before start up. Element Trouble Indicates combustibles sensor failure after start up. 00 OVER 00.0 Indicates O2 concentration in excess of 40.
Calibration The GX-86’s microprocessor circuits require only a few user adjustments: combustibles span, oxygen zero, H2S span, and CO span. The remaining adjustments are made using the Auto Zero/Span function. NOTE: Adjust the GX-86 when a gas reading drifts below zero or a sensor has been replaced. Supplies and Equipment To adjust the GX-86, you will need the following supplies and equipment, available in an RKI Calibration Kit: • Known calibrating samples of combustible gas, H2S, and CO.
NOTE: The combustibles measurement is flow-sensitive. If you are using a dispensing valve instead of a regulator, use a flowmeter and set the flow rate to 1.0 SCFH (approximately 0.5 LPM). 6. Watch the GX-86 display to verify the combustibles reading matches the concentration of the calibrating sample. If the reading does not correspond with the sample, slowly adjust the COMB SPAN control. 7. Expose the sensor to fresh air and verify that the combustibles reading returns to zero. 8.
Calibration with the RKI Four-Gas Cylinder A specially mixed cylinder of gases is available from RKI Instruments that contains the following mixture: • 50% LEL methane (CH4) • 12% O2 • 25 ppm H2S • 50 ppm CO The RKI Four-Gas Cylinder is ideal for verifying or calibrating all four gas detection ranges. The ranges can be set individually or all at once, depending upon the type of calibration cup used. 1. Take the GX-86 to a non-hazardous environment before calibrating. 2.
Maintenance Batteries 1. Check the battery voltage periodically by pressing the BATT button. Replace the batteries before the voltage drops to the operational limit (see “Alarms” on page 7). WARNING: Take the GX-86 to a non-hazardous location before replacing the batteries. 2. To replace the batteries, slide the battery compartment cover off the instrument case. Remove the batteries and verify that the battery compartment and electrical contacts are clean.
O2 sensor Replace the O2 sensor when: • the O2 circuit cannot be set to 0.0 on an oxygen-free sample • the OXY (O2) display does not show 20.
Accessories Extender Cable The extender cable extends the sensor block up to 10 meters from the GX-86. You can use the extender cable to test confined spaces or for remote monitoring. The extender cable accessory includes: • cable (with sensor block plug and socket) • rubber guard (for the sensor cover) To install and use the extender cable: 1. Place the GX-86 in a non-hazardous area. 2. Verify that the GX-86 is turned off. 3. Remove the sensor cover. 4.
4. With the vinyl case on the GX-86, slide the adapter into place over the sensor cover. 5. Start-up the GX-86 and verify operation as described in “Start-up” on page 5. CAUTION: Do not place the probe tip in liquid or other materials that could be drawn into the sample-draw aspirator or the GX-86. 6. Place the probe tip in the location you want to monitor, then squeeze the aspirator bulb several times at a moderate pace. Observe the display for changes in the readings.
Appendix A: Parts List Table 5: GX-86 Parts List Part Number Description 21-1070RK Battery cover (with retaining strap) 33-7101RK Filter (charcoal) 33-7104RK Filter retainer 61-0220RK Combustible gas sensor 65-1051RK Oxygen sensor 65-2003RK Carbon monoxide sensor 65-2023RK Sulfur dioxide sensor 65-2033RK Hydrogen sulfide sensor 71-0001RK Model GX-86 Instruction Manual 16 • Appendix A: Parts List Model GX-86 Instruction Manual
Appendix B: RKI Model GX-86 Relative Response Chart NOTE: The following response chart is based on a GX-86 that is calibrated to methane.
18 • Appendix B: RKI Model GX-86 Relative Response Chart Model GX-86 Instruction Manual
