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Frequently Asked Questions

Questions

Servicing

Instruments

Field Readings

Accessories

DataField: using a computer with your GEM

Answers

Servicing

How long will I be without my instrument when I send it in for its 6-month servicing?
Your instrument will spend from 7-13 days at LANDTEC, barring unusual circumstances. However, it must also be shipped from your site to our service center, and back again. Plus, once we issue the quote, we must wait for your to return it. So, the total time is more like 2-3 weeks.
How can I minimize the service time?
  • Get an RA number and include it with the package
  • Ship overnight both ways
  • Watch for your quote and return it immediately
Can I rent an instrument while mine is being serviced?
Yes. LANDTEC offers flexible instrument rentals that can be arranged at the time you obtain an RA.
What does a Gold warranty offer over the standard warranty?
  • Parts and labor warranty extends beyond one year.
  • Two six month servicings are included
  • Repairs and calibration are completed in 5-7 business days, instead of 7-10.
  • Free loaner instrument in case the inspection plus servicing is estimated to take longer than 10 days
  • Rental instruments are offered at 25% off
  • If repair time takes more than 10 days, return shipping is paid for by LANDTEC
What does a Platinum warranty offer over the Gold Warranty?
The platinum warranty is designed for installations that need to maintain a fleet of instruments.
If I use my GEM infrequently, should it still be serviced every six months?

You should service your GEM no less than once a year, regardless of its frequency of use.

This is due, in part, to the nature of gas sensors. Electrochemical gas sensors, such as the Oxygen sensor, get used up and must eventually be replaced. Whether or not your instrument is turned on, the sensor is always working and therefore wearing out.

Can I buy a GEM-2000 replacement battery and install it myself?
No, the battery must be replaced by LANDTEC.
If I am sending in my instrument to fix the computer connection, should I also send in the cables?
Yes. A problem connecting an instrument to a computer may be caused by a faulty cable, which can only be diagnosed by testing the cable in our service facility.
If I am sending in my instrument to fix bad temperature readings, should I also send in the temperature probe?
Yes. Your faulty temperature readings could be due to the probe. This possibility shoud be investigated at the LANDTEC service facility.

Instruments

Using GEM-500 parts with a GEM-2000

Can the GEM-500 battery charger be used with the GEM-2000?
No.
Can the GEM-500 temperature probe be used with the GEM-2000?
No.
Can I use my GEM-500 serial cable with the GEM-2000?
No.

GEM-2000 & GEM-2000+

What is the difference between a GEM-2000 and a GEM-2000+?
A GEM-2000+ has built-in analyzers for H2S and CO. The GEM-2000 requires external gas pods to monitor these gases.
Does the GEM-2000 running in GA mode read flow?
No. GA mode mimics the operation of the GA-90, which is used only to sample gas composition, not to measure flow.
Can I set the time&date in my GEM-2000 without using DataField?
No.
What is lost during a cold start?
Everything. All readings stored in the instrument, all Well IDs, the Date and Time, all other settings.
How long can I realistically expect to use my GEM-2000 on a full battery charge?
About 8 hours. This is assuming a pump running time of 120 seconds, and a "normal" well field. Of course, your time will vary with such factors as the age of your battery, the number of actual wellheads you read and their type, and so on.
Can I reset the barometric pressure?

No.

This question arises because the barometric pressure shown on the GEM-2000 screen and attached to your readings is not corrected to sea level, nor is it temperature compensated. So, if you are taking readings at 3000 feet, your barometric pressure will be too low.

If it is important that a corrected barometric pressure be attached to your readings, you should stamp your readings with the correct value after they're downloaded. The best way to know the correct barometric pressure is to have a professional grade barometer on site. If this is not possible, you can use a barometric pressure correction calculator online to derive the corrected pressure from the one the GEM displays. You can find one here: http://www.csgnetwork.com/barcorrecthcalc.html

You stamp readings in DataField CS after you download them from the instrument. Click on "Technician & Weather Stamping" and enter the correct barometric pressure and other information in the form that pops up.

Can I read H2S and CO with both the GEM-2000 and GEM-2000+?
Yes. The GEM-2000 requires that an external gas pod be used, while the GEM-2000+ has built-in Hydrogen Sulfide and Carbon Monoxide detectors.
What is the range for H2 detection in the GEM-2000+? For the external gas pod?
0-200ppm.
What is the battery recharge time for the GEM-2000?
ABout 2-3 hours.
My GEM-2000 won't turn off.
Press and hold the on/off button. Your GEM-2000 will shut off in 15 seconds or less.

Filters

What is a carbon filter and why do I need one?
A carbon (or charcoal) filter reduces the quantity of non-methane hydrocarbons in the gas stream, which ensures a more accurate methane level reading.
What is a water trap and why do I need one?

The water trap is a filter that removes water from your gas stream. Without this, moisture could be drawn into the body of your GEM where it can do permanent, or at least very expensive, damage.

If you are using a charcoal absorber filter, the water trap should come before the charcoal absorber. That is, the charcoal filter should be closer to the instrument.

What is a particulate filter and why do I need one?

A particulate filter removes small particles—dust, pollen and so forth—from the gas stream. This is important because particles degrade the instrument's performance and must eventually be cleaned out during servicing.

The particulate filter is inside the GEM-2000 body, in the back behind the circular door with the large slot in it. The door can be opened with a quarter or something similar. Slide the quarter into the slot and turn counter clockwise.

The particulate filter should be checked regularly, at least every three months, and replaced immediately if it is clogged.

WellIDs

My GEM insists on 8 character ID's. My well IDs don't need 8 digits. What do I do?
The well IDs must have 8 characters—that's letters or numbers, no punctuation. A commonly used technique is to use a four or five letter abbreviation for the landfill, followed by a three or four digit zero-prefixed well number. So, if you own the Smith County Landfill, you might identify your wells as: SMITH001, SMITH002, SMITH003 and so on.
Can the GEM-500 use the same Well ID list that the GEM-2000 uses?

Yes, with restrictions.

The GEM-500 does not support the full range of features that the GEM-2000 does, such as custom pump running time, info labels and custom questions.

If you create a Well ID list using these features in DataField , then upload the list to the GEM-500 and subsequently download that same Well ID list, you'll find that the non-supported features are gone.

The correct way to handle Well ID lists is to create them in DataField and save them in files on your computer, thus ensuring that the list is not lost. Then when the Well ID list is needed, load it into DataField, then upload to your GEM-500 and/or GEM-2000 instruments. Because the list is already saved on your computer, you will never have to download it from the instrument.

Field Readings

How do temperature extremes affect my readings and instrument? What can I do to work in extreme temperatures?

Above 104°F (40°C) or below freezing, 32°F (0°C), your readings may be incorrect, or the instrument may otherwise malfunction. In extreme heat, the GEM-2000 screen goes black.

If you are working in sub-freezing temperatures, you can use a hand warmer to keep the instrument warm. You might also keep the instrument inside your coat.

In extreme heat, try to keep the instrument out of the direct sun. If its readings become erratic or the screen goes black, bring it into a cooler environment, such as your air-conditioned truck.

Why is my methane reading so high?

You probably have other hydrocarbons in your gas. The methane detector is sensitive to all hydrocarbons, so the presence of ethane, propane, butane and others in your gas stream will cause your methane reading to be too high.

LANDTEC sells "Charcoal Absorber Filters (1-00000-5084)", which will reduce the contamination from non-methane hydrocarbons.

For more information, see section 4.6 "Cross Gas Effects" on page 11 of the GEM-2000 manual.

Why are my readings erratic? My Methane reading is rising and falling for no apparent reason.
Readings, especially Methane, can be affected by cell phones. Do not use your cell phone while you are taking field readings.
What is a "cross-gas" effect?

Some gas sensors are sensitive to more than one type of gas. Methane sensors, for example, measure hydro-carbon bonds, which are present in all hydrocarbons, such as Ethane, Propane, Butane and others. So, if these other gases are present, your GEM will read them as Methane, and therefore report more Methane than is actually present.

Because landfills are known to contain large amounts of Methane, and don't normally contain these other hydrocarbons, this cross-gas contamination is not usually a problem.

The Oxygen and Carbon Dioxide sensors in the GEM instruments are relatively free of cross-gas effects.

The H2S and CO sensors in the gas pods and the GEM™2000 Plus do show some cross-gas effects. The GEM™2000/GEM™2000 Plus manual has a cross-sensitivity table for these sensors.

Accessories

What should I do with my empty calibration gas canisters? Can I recycle or refill them?
They can't be refilled. Local and state regulations will govern their disposal, recycling or return. Please consult your local agencies for more information.
How long will my calibration gas cylinder last?

Short answer: about 15-17 calibrations.

Long answer:

  • The gas cylinder volume is 0.6 cubic feet (17 liters).
  • The gas flow rate with the regulator set at 0.5 is about 1/2 liter per minute.
  • At 1/2 liter per minute, one bottle equals 34 minutes.
  • An average calibration will take two minutes for each gas.
  • So, a gas cylider holds about 17 calibrations.

DataField: using a computer with your GEM

After I installed DataField, I got two desktop icons: DataField CS and DataField Online. Which one do I use?

DataField OnLine is an online service that must be purchased separately from the instrument. If you have not contracted for DataField Online (also called EnviroComp), then you can ignore or delete the "DataField OnLine" icon. The icon itself is simply an Internet shortcut to the EnviroComp site hosted at LANDTEC.

DataField CS is software that runs on your own computer, and works without any additional purchase. It allows you to create and manage Well ID lists, download field readings and change settings. You cannot use your GEM-2000 without DataField CS.

Is DataField CS compatible with Windows XP?
Yes. DataField CS runs properly on Windows 98/ME/2000/XP.
What are the System Requirements for DataField CS?
  • Pentium III 500 MHz microprocessor or equal.
  • 64 MB RAM.
  • 120 MB of free hard disk space.
  • CDROM drive.
  • Windows 98 or later

These requirements were common on machines sold in 2000.

How can I connect my GEM to my laptop? There is no plug that fits your cable.

The cable that lets your GEM communicate with your computer is normally plugged into a "Serial" port, sometimes called an "RS232" port. Modern laptops often lack this port. In this case you need a "Serial to USB" adapter cable in addition to the cable supplied with your GEM. That is, you will plug your LANDTEC-supplied cable into the adapter cable, which is then plugged into a standard USB port.

We use the Belkin F5U409, but any such cable will work. Check Google for adapters

I downloaded my readings, but the well IDs are corrupted (meaningless characters)?
The readings you have downloaded can't be fixed. The problem can be prevented in the future by doing a cold start of the instrument. Instructions for doing a cold start are in section 2.9 of the GEM-2000 manual.
I spent hours creating my well ID list in DataField CS, but now I can't find it on my computer anywhere. What happened?

The Well ID list you created in DataField CS was not automatically saved on your computer. To save a copy on your computer so that it is available for uploading to an instrument later, create the list, then click on the "Save File" button on the Well ID screen and choose a folder and filename that will allow you to find it later.

If you created a Well ID list, then uploaded it to an instrument but did not save it on your computer, you can recover it in DataField by going to the Well ID screen and clicking "Load from Instrument". The list will be loaded into DataField, at which point you should click "Save File" as described above.

Your Well ID list needs to be saved to your computer only once.