1.7.1 Special precautions when using the motor- ized pump The internal material used in the pump diaphragm seal is susceptible to temporary compromise by high levels of combustible fuels and solvents. If the pump is being used in an atmosphere that contains concentrations of combustible fuels and solvents that exceed 50% LEL, test the pump frequently to ensure that the seals have not been compromised. To test the pump, block the sample inlet with a finger. The pump should go into alarm. If the pump fails to go into alarm while the inlet is blocked, the pump is not working properly and the IQ Force will not be providing accurate readings. If the pump test fails, the safest course of action is to immediately leave the affected area, and return only after further testing determines that the area is once again safe for entry.