Q: Can I order directly from mPower?
A: Yes, for simple or repeat orders, just enter the Product page on our website and click on the blue “Buy Now” button to be taken to the product ordering pages and pay by credit card. If you are uncertain about any aspect of the product capabilities or ordering process, we recommend contacting your local distributor, who can assist you at no extra charge.
Q: What is a “lead-free” oxygen sensor?
A: Standard oxygen sensors are galvanic cells that use lead wool as a sacrificial reagent. This means that once the lead is gradually used up, the life of the sensor has ended. In lead-free sensors the oxygen is measured electrochemically with the help of a catalyst that is not used up. Lead-free oxygen sensors cost more initially, but can last longer and thus the cost may be about the same or less over the life of the sensors. Other advantages are being less prone to leakage and less generation of hazardous waste lead oxide compounds. Lead-free sensors require relatively high power and therefore are best implemented in rechargeable instruments such as the MUNI or POLI, but can be used in the UNI (which is non-rechargeable) with more frequent battery replacements.
Q: What is the difference between a “standard” (pellistor) LEL sensor and an NDIR LEL sensor?
A: The low-cost, standard, pellistor LEL sensors use a heated catalytic bead to oxidize any combustible gases present and therefore respond to all explosive gases including methane, hydrocarbons and hydrogen. The NDIR sensor uses an infrared lamp to measure the C-H bonds in methane and other hydrocarbons, so it cannot detect some highly flammable compounds like hydrogen or carbon disulfide. NDIR sensors are more expensive but last longer, so in the long run the costs are about the same. NDIR sensors are not affected by poisons that damage pellistor sensors, such as silicones, sulfur compounds and acids. Pellistor sensors require oxygen to function while NDIR sensors do not. Thus NDIR sensors can measure hydrocarbons accurately without oxygen present, but may overestimate explosion hazard in inert atmospheres where combustion is not possible.
Q: Why is the battery dead on the rechargeable monitor I just received?
A: All shipping companies require <20% battery charge to maximize freight safety. If a distributor does not recharge the battery before forwarding, it may become fully discharged before reaching the end user. We recommend charging the instrument immediately upon receipt and before the first use.
Q: Why is my UNI single-gas monitor beeping frequently with no gas present?
A: Although all units are calibrated before shipment, some monitors like ozone and hydrogen fluoride are sensitive to humidity and need to be re-zeroed in the local environment they are used in. Leave the unit on for a few hours the first time it is turned on, in the area of use if possible, and then re-zero. We recommend disabling the vibration alarm during this process, to save battery life.
If the TWA or STEL label is flashing at the bottom of the display, the unit will alarm even if no gas is currently present. The only way to clear these alarms is to turn the unit off and re-start (or wait a long time in clean air).
Q: Why does my UNI single-gas monitor not respond when I expect gas to be present?
A: Many electrochemical sensors require a “wake-up” if they haven’t been used for several weeks. Expose the UNI to the gas to be measured or calibration gas, for a minute or two, if it hasn’t been used recently. If there is still no response, re-zero and re-calibrate the sensor. If the unit has been used in a dusty environment, replace the on-board filter.
Q: Do I need to recalibrate my UNI MP100 if I switch concentration units?
A: No. The UNI makes the conversion automatically. For example, one could set the units to ppm, calibrate in ppm, and then switch to mg/m3 and still get the correct readings in mg/m3. Of course the user is reminded to always make sure that the concentration unit on the span gas cylinder is the same as the setting on the instrument.
Q: Why does my NEO read about 20 ppb immediately after zeroing in clean air?
A: The ~20 ppb background reading is set in clean air when the Self-Zeroing function is turned on. Self-zeroing is a unique feature, which allows the unit to re-zero automatically if the readings drift below the zero calibration signal for a some time. This keeps the readings more accurate if the baseline drifts over time because of factors like lamp aging or contamination of the sensor. To turn off and allow readings of close to 0 ppb after zeroing, enter the Monitor Setup menu and select Off for Self-Zeroing. This function is not needed if the user does a manual zero calibration on a regular basis.
Q: Do I need to recalibrate my NEO or POLI PID sensor if I change the measurement gas?
A: No. Assuming the instrument is calibrated to standard isobutylene, it will apply the correction factor for any compound in its on-board memory and display correct readings in units of ppm or ppb of the measurement compound. You can switch back and forth between any compounds without recalibrating. Of course, if a gas standard is available for the new measurement gas, it is usually better to calibrate with that to circumvent any possible inaccuracies in the correction factors.
