ELTRA ONH-2000 - 2.2 Pressure Switch Adjustment

 2002 by ELTRA GmbH Germany – January 2002 – Service Manual OH 900 / ON 900 / ONH 2000
2.2-1
2.2 2.2 Pressure switch:
The pressure switch should be adjusted to about 1 bar ( 15 psi ); this means that under
1 bar ( 15 psi ) , the contact is open ( no contact ), and over 1 bar ( 15 psi ), the contact
is closed ( turned on ).
 In installed condition and with the analyser turned on ( power switch set to pos. 2 ),
there should be a voltage of 24 VDC when the pressure is under 1 bar ( 15 psi ).
If the pressure is over 1 bar ( 15 psi ), then the voltage should be zero.
ATTENTION ! Measure this with a high-impedance digital voltmeter!
Do not cause a short circuit while measuring, or else the
electronic drivers will blow!
 If necessary, the oxygen pressure can be adjusted to 1 bar ( 15 psi ). This can be read
at the upper pressure gauge of the analyser.
 The switch point can be set by turning the screw ( 1 )
 If the switch is turned off ( 24 V ) when the pressure is at 1 bar ( 15 psi ), then the
screw ( 1 ) should be turned counter clockwise until the switch turns on, measuring
the power until it reaches zero volt.
 If zero volts are measured when the pressure is at 1 bar ( 15 psi ), the screw ( 1 )
should be turned clockwise until the voltage goes to 24 V.
1
2 -2 - 2
VDCGND
02- 02- 2b