Master(tig) 2500, 2503, 3500, 3503 MLS™/ 0311 – 7© COPYRIGHT KEMPPI OYAC FGBED2.9. SHIELD GASHandle gas bottle with care. There is a risk for injury if gas bottle or bottle valve isdamaged!Use inert gases such as argon, helium or argon-helium mixture as shield gas for TIG welding.Make sure that the gas flow regulator is suitable for the gas type used. The flow rate is setaccording to the welding current, joint form and the size of the electrode. A suitable flow rateis normally 8 – 10 l/min. If the gas flow is not suitable the welded joint will be porous. Sparkignition becomes more difficult if the gas flow is too high. Contact your local Kemppi dealer forchoosing gas and equipment.2.9.1. Installation of gas bottleParts of gas flow regulatorA Gas bottle valveB Pressure regulation screwC Connecting nutD Hose spindleE Jacket nutF Gas bottle pressure meterG Gas hose pressure meterAlways fasten gas bottle properly in vertical position in a special holder on the wall or on acarriage. Remember to close gas bottle valve after having finished welding.The following installation instructions are valid for most gas flow regulator types:1. Step aside and open the bottle valve (A) for a while to blow out possible impuritiesfrom the bottle valve. Note! Watch out for the gas flow.2. Turn the press regulation screw (B) of the regulator until no spring pressure can be felt.3. Close needle valve if there is one in the regulator.4. Install the regulator on bottle valve and tighten connecting nut (C) with a wrench.5. Install hose spindle (D) and jacket nut (E) into gas hose and tighten with hose clamp.6. Connect one end of the hose with the regulator and the other end with the power source.Tighten the jacket nut.7. Open bottle valve slowly. Gas bottle pressure meter (F) shows the bottle pressure.Note! Do not use the whole contents of the bottle. The bottle should be filled when thebottle pressure is 2 bar.8. Open needle valve if there is one in the regulator.9. Turn regulation screw (B) until hose pressure meter (G) shows the required flow (orpressure). When regulating flow amount, the power source should be switched on andthe gun switch pressed simultaneously.Close bottle valve after having finished welding. If the machine will be out of use for a longtime, unscrew the pressure regulation screw.