McNab Model AP-IF Conductivity Indicator

AP-IF_cabinet.JPG (57293 bytes)


  • Meter Displayed Set Point

  • Alarm/Controller Standard

  • Linear/Outputs

  • Temperature Compensated

  • Economically Priced

  • Rugged Construction

  • 115 or 230 VAC Operation


The Aqua-Purometer I (F) series are single range conductivity indicators and controllers. The instruments are available in six linear ranges covering the conductivity spectrum from ultra pure water to highly concentrated solutions. These instruments use proven solid state circuitry housed in a rugged, industrial cabinet to provide an economical and straight forward approach to process control instrumentation. 


The Aqua-Purometer I (F) is available in six linear ranges: 0-2, 0-20, 0-200, 0-2000, 0-20,000, and 0-200,000 micromhos specific conductance.  The solid state (IC) circuitry provides linear outputs to the panel meter and to the recorder output terminals. Since the recorder signal is linear, special recorder paper is not required. 

A unique feature of the Aqua-Purometer I (F) is the meter displayed set point.  To enter the set point, one depresses the internal Calibrate Switch and rotates the internal Set Point Control until the desired alarming point is reached by the needle on the meter scale.  Releasing the switch enters the set point.  The use of the larger meter settings than is normally scale permits more accurate possible with smaller calibrated pointer knobs.  Furthermore, because the set point is displayed on the meter, the error producing step of translating panel control calibration to meter calibration is eliminated.  Also eliminated are the errors associated with loose pointer knobs and smudged or worn-away panel control calibrations. 

The Aqua-Purometer I (F) provides both energized and non-energized, normally open and normally closed contacts for flexibility of application. The controller relay is a sealed, plug-in type with contacts rated at a husky 5 amps. The preset non-symmetrical hysteresis control circuitry eliminates relay chattering due to electronic noise. 

The power supply of this instrument can operate either on 115VAC or 23OVAC 50/60HZ via an internal switch.  Line voltage variations of +/- 10% of nominal value are easily handled.  The power supply is transformer isolated and fuse protected. 


The cabinet is made of all-welded construction of sturdy No. 18 gauge steel. A hinged front door provides easy access for routine inspection or servicing. Servicing is further facilitated by the use of plug-in replacements for the most serviced components. A rubber gasket provides a water resistant seal around the cabinet door.  The door is provided with a NEMA-4 type latch. The cabinet is designed for wall, or semi-flush mounting (with optional kit).  The panel has a visually pleasing gray exterior which is set off by silver and black artwork. The amber power-on and the red alarm lights are 180 easy viewing, long life neon lamps.  The meter is a rugged industrial type with an easily read, color accented scale. All controls except the power switch are internal for tamper-proofing. 

The Cell 

AP-IF_cell.JPG (25796 bytes)The Aqua-Purometer I (F) uses McNab screw-in style cells.  A typical cell is shown at left.  This cell design minimizes the trapped air problems associated with many competitive designs.  Standard and 1 NPT sizes are available.  Cells are supplied with a six-foot, dressed cable.  For explosion-proof cells or other special applications, contact McNab

Electrical Installation

AP-IF_electrical_installation.JPG (41942 bytes)


Model AP-IF
Ranges Available (Micromhos-CM)
0 2
0 20
0 200
0 2000
0 20,000
0 200,000
Accuracy 2% of scale as calibrated
Controller Internal control adjusts set point which is displayed on meter during adjustment procedure.  Outputs: AC line voltage energized normally open and normally closed.  Non-energized normally open and non-energized normally closed also provided.
Relay Sealed, plug-in type.  Contacts rated at 5 amps (resistive)
Remote Output Linear 0 1mA for remote meter or recorder
Temperature Compensation Automatically corrects water temperature of 0 100 C to 25 C
Maximum Cell Pressure 150 PSI
Maximum Cell Temperature 135 C
Power Requirements 115 VAC +/- 10%, 50 to 60 Hz or 230 VAC +/- 10%, 50 to 60 Hz.  Either voltage may be selected by internal switch.
Mounting Style Wall or semi-flush with optional kit.
Weight 6 lbs (panel only)
Options Alarm Bell, semi-flush mounting kit, cell test resistor, drip shield, 100 ft. cell cable, explosion proof housing, special electrode materials, ultra-clean cells.


View probe specifications for the AP-I family of McNab analyzers.


383-2 East 29th Street | Buena Vista, VA | USA 24416-1293

540.261.1045 voice | 540.261.1268 fax |

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