Our air samplers are durable. A customer once sent a UPAS in for service that had a record 8000+ hours of run time on it and, after a quick flow rate recalibration, we sent that UPAS back out to do some more sampling. Another time we had a customer send back a UPAS that had been run over by a forklift; that one received a new housing and was back in the fight for clean air in no time—amazing!
We put a sticker on the back of each UPAS so you know when the UPAS was last calibrated with a reference flow meter. We put a nominal one-year expiration on the calibration sticker. Unlike a laboratory balance, the need to send UPAS in for service can vary, which is a good thing. We know that our customers use UPAS all over the world and we want to help keep your air sampling campaigns up and running as much as possible.
If your calibration sticker has recently expired but you are periodically checking your sample flow rates against a high-quality external flow meter, you are probably fine to keep sampling.
Another way to gauge whether it’s time for a check-up is to run the UPAS for a short period of time and review the log file. The total run hours on the device will be listed in the file header. If it’s been >2000 hours since the UPAS was last serviced, consider sending it in for recalibration. We do observe a very slow drift in UPAS flow rate after several thousand hours of use.
There are additional reasons to send in your UPAS for a professional evaluation. We will look for signs of age and deterioration that may require attention even if there are no symptoms. For example, after thousands of hours of use, we occasionally identify corrosion on the circuit board from exposure to the elements. Corrosion can cause issues with microSD card data storage, UPAS charging, and firmware. When UPAS are returned, we evaluate for corrosion damage as well as for ingress of dust or debris.
Once we we receive your UPAS and conduct our intake analysis, we’ll give you a report on the state of the equipment and make some recommendations to bring your UPAS back up to like-new performance.
If you have units not functioning properly in the field, we can often provide feedback remotely if you send us a log file that was collected in ‘debug mode.’ In debug mode, the UPAS logs data that our engineers can use to identify likely explanations for unusual behavior. Our most common finding from evaluating a log file from a misbehaving UPAS is that the battery was not charging, which can happen if power at the field site is unreliable. In this case, we can usually see from a UPAS log file there was not an increase in battery voltage from one sample run to the next—a telltale sign of a weak link in charging.
You can update your UPAS firmware to the latest version without sending the device back to us. Download the latest firmware file from the appropriate product page; then, install the new firmware on the UPAS using the instructions provided in the User Guide.
We also recommend checking the UPAS sample flow rate against an external flow meter on a regular basis. We recommend using Alicat Whisper series flow meters with all of our air sampling products. See the product User Guide for (a) information on the specific model numbers of flow meters that we recommend and (b) instructions for performing a sample flow rate check.