Frequently Asked Questions
Gauge Pressure Transducers

 Contegra Inc
Eagan, MN
651-905-0900

Table of Contents

  1. GPX 220 pressure connection
  2. What makes the GPX 220 electrically superior?
  3. What is the temperature performance of the freeze protection sold with the SLX 220 and GPX 220?
  4. GPX 220 pressure ratings
  5. GPX standard pressure gauge sizes

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GPX 220 pressure connection

The GPX 220 pressure port is 1/4" female NPT.

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Last edited 6/2/03

What makes the GPX 220 electrical protection superior?

The GPX's sensor is electrically isolated from the sensed media.  Many competitive products plumb the sensor (with a metal housing) directly to the pressure line or they incorporate an interposing gauge guard (for isolation) which is metallic.  If their sensor is connected to a city water main, a lightning strike can easily be conducted by the water to the metal housing of the sensor and destroy it.  The GPX 220 uses a plastic gauge guard with a silicone oil fill for electrical isolation from the media. 

The GPX 220 has the same electronics as the T420, providing three levels of transient protection on the 4-20 mA loop:  a gas tube arrestor for suppression of high voltages, transorbs, and varistors for fast clamping of lower voltage transients.

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What is the temperature performance of the freeze protection sold with the SLX 220 and GPX 220?

The thermostat turns on at 55 degrees F and off at 85 degrees F. The standard enclosure is uninsulated. The following chart shows the maximum differential temperatures (°F) maintained:

Product SLX 220 GPX 220
Wattage 50 100

Uninsulated enclosure

 Indoors 36º 36º
Outdoors 23º 24º
 Insulated enclosure 100º+ 100º+
 Enclosure dimensions 8H x68W x46D 12H x 10W x 6D

Higher thermostat settings and enclosure insulation are available options.

Last edited 7/5/00
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GPX 220 Pressure Ratings

The GPX 220 sales literature states:  "Pressure Overload is Five times full scale of the sensor (gauge guard to 500 PSI waterhammer)."  (brochure 10012-0001-01)

As of June of 2000, the standard overpressure rating of the gauge guard is 200 PSI.  This new gauge guard has superior accuracy and less temperature error.  200 PSI sensors may optionally be ordered with the higher pressure gauge guard.

 

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Last edited 7/5/00

Pressure gauges provided with the GPX

The standard pressure gauge provided with the GPX when ordered with the "G" option is as follows:

Sensor

Range

 Gauge

Provided
15 30
30 60
75 160
100 160
200 300

Many 75 PSI sensors are sold with full scale readings less than 66 PSI.  In those cases, we provide a 100 PSI gauge.  Standard gauge ranges are zero to 15, 30, 60, 100, and 160 PSI

 

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Last edited 10/1/02
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FAQs
GPX 220
GPX 100
Copyright © 2001  Contegra Inc.   All rights reserved.
Revised: April 19, 2005.