The optional Purge circuit is available in the S4000/4040/4020 and allows the user to send a purge gas through the entire system, or only a small portion of it, to flush any gas residue out of the solenoids, tubing, mass flow controllers and blend chamber.

Regular use of the Purge Mode will make the system cleaner, safer and will prolong instrument life. The Purge should be used to flush the system between the blending of gases which may be reactive, flush dust and other particles out of a system which has not been used for a period of time, or clean the system after the use of gases which will present possible risks if left in the system because of toxicity or corrosivity.