Click on one of the below links:
Free Vapor Pressure Calibration Maintenance Workshop
Grabner VPS Basic Hand Tools
Grabner VPS/H Instrument Quick Start Sheet
Grabner VPS/H Maintenance Tips
Correlation Formula for D5191 (Traditional)
1. ASTM 0.965 * Ptot - 0.548 psi
2. EPA 0.956 * Ptot - 0.347 psi
Correlation Formula for D6378 (No Sample Prep)
3. ASTM 1.000 * Ptot - 1.000 * Pgas - 0.15 psi
4. EPA 1.000 * Ptot - 1.000 * Pgas - 0.02 psi
Frequently Asked Questions:
Q- Should I verify sample temperature of 32-34°F prior to testing?
A- Yes, To comply with ASTM D5191 standards, sample must be chilled.
Q- Should I add Piston Oil to my instrument when it returns from annual tune and calibration?
A- Yes, be sure to add a small amount of Piston Oil (0.1 mL) to prevent o-ring from drying out and/or possible piston errors. Possible tipping of the unit during shipping can cause oil loss. Refer to your user manual section 12.3 (Maint & Troubleshooting). To re-order Piston Oil, mention part #20111.
Q- What if my Pgas is too high - above approximately 1 psi?
A- Luer inlet or inlet tube is leaking (air introduction), Replace inlet tube or luer inlet.
Q- What if my instrument also fails a leak test?
A- Your cell is probably leaking due to worn O-ring/valve packing.
Replace piston O-ring, Try to tighten valve first – if unsuccessful, replace valve.
Q- What if my measurement results are wrong?
A- Your sample is either too cold (high Pgas) or too warm (low Pgas).
Adjust sample preparation/handling procedures according to Standard; 32–34º F.
Q- What if the wrong measuring temperature is programmed?
A- Verify measuring temperature is 100ºF.
Q- What if my DVPE results are wrong?
A- You probably have an improper/wrong correlation formula.
Check/Adjust correlation formula (see formula above).
Q- What if I receive the following message error: *error piston motor?
A- Microswitch needs adjustment or is completely worn/faulty.
Piston can not reach desired position because of binding O-ring.
Adjust/replace microswitch, Oil/replace O-ring.
Q- What if RAM fails appear continuously when instrument is turned on?
A- Backup battery is defective (Voltage: below 2.4V new type battery / below 3.6V old type)
when instrument is switched off. Replace back up battery.
Q- What if my Instrument resets to main menu after gas correction?
A- Heating/cooling field effect transistors are shorting when switching.
Replace (4) FETs on Regulator/Amplifier PCB.
Q- What if my DVPE results are wrong?
A- Wrong formula was set or chosen or Sample preparation was not correct according standard.
Set correct formula according the required standard;
Comply with sample preparation according standard.