Pressure Switch Replacement

SPS 4001B

Instruction Manual

IM-106-340AC-1, Rev. 1.0 April 2005

Use the following procedure to replace pressure switch (16, Figure 4-1).

1.Remove the SPS 4001B chassis from the enclosure according to the instructions in "Remove/Install Chassis".

2.Remove lead wire terminals from pressure switch (16).

3.Use a 1-1/16 in. 6-point socket to loosen and remove switch (16).

CHECK VALVE REPLACEMENT

PRESSURE

REGULATOR MAINTENANCE

FLOW METER ADJUSTMENTS

When installing the pressure switch, do not overtighten. Damage to the solenoid may occur.

4.Install new pressure switch (16). Be careful not to overtighten. Connect the leads to the pressure switch terminals. Polarity does not matter.

5.Install the SPS 4001B chassis in the enclosure according to the instructions "Remove/Install Chassis".

The check valve (Figure 1-3)may stick or become plugged over time. Replace when necessary. If condensation deposits are noted upon removal, consider insulating the check valve.

The reference air pressure regulator (22, Figure 4-1)is factory set to 20 psi (138 kPa). If necessary, use the knob on top of the pressure regulator to readjust the pressure setting. Refer to "Remove/Install Chassis" to access the pressure regulator for adjustment.

Calibration Gas Flow Meter

Calibration gas flow meter (26, Figure 4-1)regulates the calibration gas flow. The flow meter requires readjustment only after installing a new diffusion element on the Oxymitter 4000 probe. Adjusting the flow meter at any other time can pressurize the cell and bias the calibration.

In applications with a heavy dust loading, the O2 probe diffusion element may become plugged over time, causing a slower speed of response. The best way to detect a plugged diffusion element is to note the time it takes the Oxymitter 4000 to return to the normal process reading after the last calibration gas is removed and the calibration gas line is blocked off. A plugged element also can be indicated by a slightly lower reading on the flow meter.

Change the diffusion element when the calibration gas flow meter reads slightly lower during calibration or when the response time to the process flue gases becomes very slow. Each time the diffusion element is changed, reset the calibration gas flow meter and calibrate the Oxymitter 4000. For more information on changing the diffusion element, refer to the instruction manual for the Oxymitter 4000 in use.

Reference Air Flow Meter

Reference air flow meter (25) regulates the reference air. Adjust the flow with the knob on the bottom of the reference air flow meter when necessary.

4-6