Dickson PW4 and PW8 Pressure Chart Recorders

Dickson PW4 and PW8 Pressure Chart Recorders

The Dickson PW4 and PW8 provide a continuous paper record of pressure at the measurement point for equipment monitoring, testing, troubleshooting and permanent visual documentation.

  • PW4 compact recorder with a 4-inch circular chart
  • PW8 high-resolution recorder with an 8-inch circular chart
  • Pressure ranges from 0–100 PSI up to 0–1000 PSI
  • 24-hour or 7-day recording configurations
  • Pressure accuracy of ±2% of full scale
  • IP66/NEMA 4X weather-resistant enclosure
  • 1/4-inch NPT process connection
  • Operates for approximately one year from one AA battery

Permanent Pressure Records Without a Computer

Dickson PW Series pressure chart recorders continuously trace pressure against time on a circular paper chart. The completed chart provides an immediate visual history at the equipment, making it easy to identify operating cycles, pressure loss, regulator behaviour and abnormal events without downloading electronic data.

PW4 provides a compact 4-inch chart format, while PW8 uses a larger 8-inch chart for easier reading and greater visual resolution. Both are battery operated and designed for stem or wall mounting.

Choose PW4 or PW8

Selection pointPW4PW8
Chart diameter 4 inches / 101 mm 8 inches / 203 mm
Main advantage Compact size for crowded equipment and temporary work Larger chart for easier reading and better visual detail
Pressure ranges Current options include 0–100, 0–200, 0–300 and 0–500 PSI Current options include 0–100, 0–200, 0–300 and 0–1000 PSI
Chart rotation Switchable 24-hour or 7-day recording 24-hour or 7-day period according to the selected model
Response time Approximately 1 second Approximately 1 to 5 seconds
Dimensions Approximately 6.25 × 6 × 2.9 inches Approximately 10.3 × 9.5 × 3.6 inches
Weight Approximately 1.8 lb Approximately 2.9 lb
Best fit Compact installations and straightforward routine trending Applications where chart readability and trend detail are priorities

PW4 Model and Pressure-Range Selection

ModelPressure rangeChart operationRecommended starting point
PW470 0 to 100 PSI 24-hour or 7-day switchable Lower-pressure water, air and equipment monitoring
PW474 0 to 200 PSI 24-hour or 7-day switchable General industrial systems requiring more than 100 PSI
PW476 0 to 300 PSI 24-hour or 7-day switchable Compressed-air and medium-pressure equipment
PW479 0 to 500 PSI 24-hour or 7-day switchable Higher-pressure hydraulic or process applications

Confirm the exact currently orderable model code and compatible chart reference when requesting a quotation. Dickson product revisions may change the code used for a particular range or chart mechanism.

PW8 Model Selector

Pressure range7-day model24-hour modelSelection note
0 to 100 PSI PW860 PW861 Choose when all expected pressure remains within 100 PSI
0 to 200 PSI PW864 PW865 Suitable for systems requiring additional headroom above 100 PSI
0 to 300 PSI PW866 PW867 Common choice for medium-pressure industrial systems
0 to 1000 PSI Not listed as a standard 7-day model PW875 For high-pressure applications requiring a 24-hour chart

Match the chart to the recorder: chart diameter, pressure scale and recording period must all match the selected PW model. A chart with the wrong range or time base produces a misleading record even if the mechanism is operating normally.

Full-Scale Accuracy by Range

The stated accuracy is ±2% of full scale, so selecting a wider range increases the absolute pressure uncertainty.

Full-scale range±2% of full scaleSelection implication
100 PSI ±2 PSI Best useful resolution when the process safely remains below 100 PSI
200 PSI ±4 PSI Provides more headroom with a larger absolute uncertainty
300 PSI ±6 PSI Select only when the process requires the 300 PSI range
500 PSI ±10 PSI Available in the compact PW4 family
1000 PSI ±20 PSI High-range PW8 option for applications approaching 1000 PSI

Select the lowest range that safely covers normal operation, startup, shutdown, regulator failure and expected pressure surges. Never expose the recorder beyond its permitted pressure limit.

PW Series General Specifications

SpecificationPW4 and PW8
Measurement channels One pressure channel
Pressure accuracy ±2% of full scale
Chart periods 24 hours or 7 days
Process fitting 1/4-inch NPT thread with 5/8-inch hex
Enclosure NEMA 4X weather- and water-resistant case with window
Ingress protection IP66
Operating temperature Approximately −30 to +50 °C
Operating humidity 0 to 95 %RH, non-condensing
Power supply One user-replaceable AA battery
Typical battery life Approximately one year under normal conditions
Mounting Stem mounting or wall mounting using the keyhole provision
Included items AA battery, red pen and quick-start guide
Chart paper Sold separately and selected according to size, pressure range and recording period
Calibration options Available; confirm required points and certificate type

Choose 24-Hour or 7-Day Recording

Recording periodRecommended whenTrade-off
24 hours Daily tests, commissioning, shift analysis and faster pressure cycles Time markings are easier to read, but the chart must be replaced daily
7 days Weekly equipment trending and unattended routine monitoring Longer coverage with less time detail for short-duration events

Choose the period according to the shortest event that must be visible. A 7-day chart may show that pressure changed but provide less precise event timing than a 24-hour chart.

Typical PW Pressure Recorder Applications

ApplicationWhat the chart can revealInstallation priority
Compressed-air systems Compressor cycles, pressure loss and demand-related fluctuations Protect the recorder from condensate, oil and pressure spikes
Water and pump systems Pump cycling, pressure decay and intermittent supply problems Consider water hammer and use suitable pressure accessories
Hydraulic equipment Operating-pressure patterns during equipment cycles Verify medium compatibility and maximum transient pressure
Regulator performance Pressure stability and changes under varying demand Install at the correct upstream or downstream measurement point
Pressure testing Time-based record of the applied test pressure Confirm that range, accuracy and chart resolution meet the test procedure
Maintenance troubleshooting Intermittent changes that may be missed during manual observation Synchronise the chart time with maintenance and equipment records

PW Chart Recorder or PR Data Logger?

Selection pointDickson PW4/PW8Dickson PR125/PR325/PR525
Record format Physical circular chart with a continuous pen trace Electronic time-stamped readings
Pressure accuracy ±2% of full scale ±1% of full scale
Review method Read the chart immediately without a computer Download and analyse data using compatible software
Event detail Depends on chart size, pressure scale and rotation period Selectable sampling interval down to 1 second
Consumables Compatible chart paper, pen and battery Battery and any required data-transfer media
Best fit Simple visual records and established paper-chart procedures Detailed electronic analysis, export and reusable data files
Product information Current PW4 and PW8 products Explore Dickson PR Pressure Data Loggers

Charts, Pens and Routine Maintenance

Use chart paper made for the recorder's chart diameter, pressure range and rotation period. Charts are single-use records and should not be reused. Keep sufficient compatible charts, pens and AA batteries available for the monitoring schedule.

  • Replace each chart at the end of its recording period.
  • Check that the pen trace is clear, continuous and aligned with a known pressure.
  • Replace a dry, damaged or intermittent pen before starting an important study.
  • Confirm the chart keeps time and completes its rotation at the specified period.
  • Inspect the enclosure seal, window, hinges, fitting and mounting point.
  • Schedule calibration according to accuracy requirements, usage and instrument history.

Dickson PW4 and PW8 Supplier and Technical Support

Seacom Process Instruments supplies and supports Dickson PW4 and PW8 pressure chart recorders, compatible charts, pens and accessories for industrial pressure monitoring in Malaysia and international markets.

Our team can help select the chart size, pressure range, recording period, calibration option and suitable consumables. We can also review replacement requirements from an existing recorder's full model number and chart reference.

Selecting a pressure chart recorder? Send us the process medium, normal and maximum pressure, possible pressure spikes, process temperature, connection size, preferred chart size, 24-hour or 7-day period and calibration requirements.

Download

  Dickson Catalogue   (1.81M)


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