396P + 396PVP Sensors Instruction Manual

Section 5: Maintenance

LIQ_MAN_396P_396PVP

August 2013

 

 

Section 5: Maintenance

5.1General Information

The 396P and 396PVP Sensors require minimum maintenance. The sensor should be kept clean and free of debris and sediment at all times. The frequency of cleaning by wiping or brushing with a soft cloth or brush is determined by the nature of the solution being measured. The sensor should be removed from the process periodically and checked in buffer solutions.

DANGER

BEFORE REMOVING THE SENSOR, be absolutely certain that the process pressure is reduced to 0 psig and the process temperature is lowered to a safe level!

If the sensor will not calibrate, refer to your analyzer/ transmitter instruction manual for proper test procedures. If it is determined that the sensor has failed, it

5.2Automatic Temperature Compensator

The temperature compensator element is temp erature sensitive and can be checked with an ohmmeter. Resistance increases with temperature.

The 3K element will read 3000 ohms ±1% at 25°C (77°F) and a Pt100 will read 110 ohms. Resist- ance varies with temperature for a 3K and Pt100 element and can be determined according to Table 6-2 or the following formula:

RT=RO [l+R1 (T-20)]

Where RT = Resistance

T = Temperature in °C

Refer to Table 6-1 for RO and R1 values

5.3396P & 396PVP pH Sensors

5.3.1Electrode Cleaning

If the electrode is coated or dirty, clean as follows:

1.Remove the sensor from process.

2.Wipe the glass bulb with a soft, clean, lint free cloth or tissue. If this does not remove the dirt or coating, go to Step 3. (Detergents clean oil and grease; acids remove scale.)

3.Wash the glass bulb in a mild detergent solution and rinse it in clean water. If this does not clean the glass bulb, go to Step 4.

CAUTION

The solution used during the following check is an acid and should be handled with care. Follow the directions of the acid manufacturer. Wear the proper protective equipment. Do not let the solution come in contact with skin or clothing. If contact with skin is made, immediately rinse with clean water.

4.Wash the glass bulb in a dilute 5% hydro chloric acid solution and rinse with clean water. Soaking the sensor overnight in the acid solution can improve cleaning action.

Maintenance

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Emerson instruction manual Maintenance, General Information, Automatic Temperature Compensator, 396P & 396PVP pH Sensors