Algas SDI VAPORAIRE M-Series, Operation & Maintenance Manual

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Operation
4-30
Algas-SDI Operations & Maintenance Manual – P/N - 54264
LOW VAPOR PRESSURE SWITCH
The mixer requires a minimum Low Vapor Pressure for the venturi to mix gas.
The Low Vapor Pressure Switch is wired normally open and is set to close when
there is adequate vapor pressure to operate the venturi. The vapor pressure will
close the Low Vapor Pressure Switch and activate the Mixed Gas Operating
Pressure Control Switch. The Mixed Gas Operating Pressure Control Switch will
cycle the venturi based on load. If Vapor Pressure decreases below the Low
Vapor Pressure Switch setpoint, the mixer stops mixing due to low vapor
pressure, the mixer is in standby until low vapor pressure increases. The Mixed
Gas Operating Pressure Switch and Venturi Valve are not allowed to operate
until the there is adequate vapor pressure to operate the venturi.
1. Put the system on a load so that the single venturi is cycling On/Off. Slowly
throttle the LPG vapor outlet valve on the vaporizer outlet. This reduces the
LPG vapor pressure being sent to the mixer. Observe the LPG vapor
pressure gauge and note the pressure at which the venturi stops mixing, the
observed pressure is the Low Vapor Pressure Switch setpoint.
Compare this value with the Data Sheet .
2. Adjusting Low Vapor Pressure Switch setpoint ( Refer to data sheet for
setpoint ). Repeat the throttling procedure to adjust the Low Vapor Pressure
Switch by turning the adjusting wheel so that low vapor pressure setpoint
match the value given in the
Data Sheet .
See Troubleshooting Section Table 3 for annunciator display on the
SEQUNCER.