The bypass valve on a self-contained breathing device should be opened if（）.
1、When the starting air valve closes on
When the starting air valve closes on one cylinder, another starting air valve has （） opened on another cylinder whose piston has just commenced its downward stroke.AjustBnearlyCmerelyDalready
2、In setting the valves on a steam-smoth
In setting the valves on a steam-smothering system on a tank vessel，the master control valve to cargo tanks should be（）.Aopen and individual...
3、Safety valves on a boiler vent to the
Safety valves on a boiler vent to the （）.Afuel tankBbilgeCatmosphereDauxiliary exhaust line
4、The valve on the discharge side of a c
The valve on the discharge side of a cargo pump on a tanker will usually be a（）.Abutterfly valveBspectacle valveCcheck valveDglobe valve
5、The expansion valve on a Freon system
The expansion valve on a Freon system controls the （）.Asuperheat of the gas leaving the compressorBback pressure in the evaporatorCtemperature of the iceboxDsuperheat of the gas leaving the evaporator
6、In setting the valves on a steam-smoth
In setting the valves on a steam-smothering system on a tanker，the master control valve to cargo tanks should be（）.Aopen and individual tank...