My instrument tells me that calibration is due. What do I have to do?

Answer: Shawcity recommends service and calibration once every 12 months. 
Contact us for more information.

My instrument reads very high, even after I did a custom calibration. Why?

Answer: The span gas portion of the custom calibration may be inaccurate. Set back to factory calibration and see if you get a similar response. If yes, then ensure there is not some high levels of VOC present. Remove lamp and clean, blow out cell and re-calibrate. Contact us if this fails.

Q.Can you calibrate the TVOC Total VOC Monitor with another gas rather than the standard calibration gas Isobutylene ?

• A. Yes.  Here is the approach..

The cal gas must deliver a response within +-50% of a 100 ppm  Isobutylene response in order for the instrument to calibrate.  This will vary with the gas. 

With a low boiling point and small size of C4-C7 hydrocarbons you can use at least 1000 ppm. C8-C10: at least 100 ppm C11-C13, 10 ppm. For C6+,  calibration bottles should be stored and used at at least 15 deg C

For Example : Cylcohexane is sufficiently volatile and ‘PID’able to deliver this. The RF is 3. You will need  a concentration /  bottle of 300 ppm Cylcohexane in air. That will give the same response as isobutylene.

Follow the standard calibration procedures in the TVOC manual and on calibration set the gas concentration to the calibration concentration: 300. (An entry of between 10 and 400 is possible here). The instrument is now calibrated to Cylcohexane.

Can I calibrate my GasCheck?

Answer: You can bump test the unit using the supplied CalCheck Helium unit. If the instrument is out of calibration please send to Shawcity.

Can my GasCheck G2 measure more than one gas?

Answer: No. The GasCheck G2 is programmed and calibrated to only one single gas (as requested by the customer) and to one unit of measurement. For multiple gas search, the GasCheck G1 or GasCheck G3 would be the right instruments, although the G1 can not specify which gases are being detected.