Dickson Circular Chart Recorders – Temperature, Humidity, Pressure & Universal Input

Dickson circular chart recorders provide a paper record of temperature, humidity, pressure or external transmitter signals, depending on the model. Select the recorder by measurement type, chart size, recording period and installation requirements.

Temperature and humidity: KT8 and TH8 models for temperature-only or combined temperature and relative humidity recording.
Pressure: PW4 and PW8 families with 4-inch or 8-inch circular charts.
Universal input: Legacy ET855 recorder information for existing voltage and current signal installations.
Replacing an older recorder? Refer to the model comparison below before ordering a replacement or consumables.

Description
Attachments

Keep a visible record of changing conditions with a Dickson circular chart recorder. A rotating paper chart allows operators to review trends at the instrument and retain completed sheets with inspection or process records.

The range covers temperature, relative humidity, pressure and universal-input recording. Select the recorder by measurement type, chart size, recording period and installation requirements.

Compare Dickson chart recorders by size

Smaller recorders suit installations with limited space, while larger charts provide more room to review recorded trends. Sizes below refer to the nominal chart diameter, not the enclosure dimensions.

Chart size	Models / family	Measurement	Selection guidance
3-inch Approx. 76 mm	SC3	Temperature	Miniature temperature chart recorder for confined spaces. Confirm the required temperature range and matching chart.
4-inch Approx. 102 mm	SL4 SL4100 / SL4350	Temperature	Compact recorder with digital display, single AA battery operation and 24-hour or 7-day recording. Select the appropriate temperature range.
4-inch Approx. 102 mm	PW4	Pressure	Select the pressure range, 24-hour or 7-day configuration and suitable process connection.
6-inch Approx. 152 mm	KT6P1 / KT6P2 / KT6P5	Temperature	Legacy models. Consider KT8-30 or relay-equipped KT8-30R after checking the application. Moving to an 8-inch recorder requires different charts and an installation-space check.
6-inch Approx. 152 mm	TH6P1 / TH6P2 / TH6P3	Temperature and humidity	Legacy models. Consider TH8-10 for ambient sensing or TH8-11 for remote sensing, subject to configuration review.
8-inch Approx. 203 mm	KT8 KT8-20 / KT8-21 / KT8-30 / KT8-30R / KT8-31 / KT8-31R / KT8-40 / KT8-50	Temperature	Single or dual temperature channels, depending on model. Select thermistor, Type K thermocouple, RTD or ambient temperature sensing. Relay options are model-dependent.
8-inch Approx. 203 mm	TH8 TH8-10 / TH8-11 / TH8-11R	Temperature and humidity	Two-pen recording. Choose ambient sensing, remote sensing with an extension cable, or a remote-sensing model with an alarm relay.
8-inch Approx. 203 mm	PW8	Pressure	Larger pressure chart format. Confirm the complete model, pressure range, recording period and process connection.
8-inch Approx. 203 mm	ET855 / ET8	Universal current / voltage input	Legacy two-channel recorder for compatible external transmitter signals. No direct successor verified; replacement selection requires an input and application review.

Chart compatibility: Diameter alone does not establish compatibility. Match the recorder model, chart part number, measurement scale and recording period. Confirm stock and configuration availability before ordering.

Older models and replacement options

Some earlier Dickson models have been discontinued. The table below identifies replacement candidates by measurement function. These are not necessarily identical replacements; confirm the sensor arrangement, recording period, alarm functions and installation requirements before ordering.

Existing model	Replacement to consider	What to check
TH8P0 / TH8P2	TH8-10	Ambient temperature and humidity recording.
TH8P3	TH8-11	Remote sensor arrangement and cable length.
TH8P5	TH8-11R	Remote sensing and alarm relay requirements.
KT8P0 / KT8P2 / KT8P3	KT8-30	Single Type K temperature channel; confirm probe and chart range.
KT856	KT8-31 / KT8-31R	Two Type K temperature channels; select the relay version if required.
TH6P1 / TH6P2	TH8-10	Change from a 6-inch to an 8-inch recorder; check mounting space and chart requirements.
TH6P3	TH8-11	Remote temperature and humidity sensing; larger chart and enclosure.
KT6P1 / KT6P2	KT8-30	Single Type K temperature recording; requires 8-inch charts.
KT6P5	KT8-30R	Single Type K temperature recording with relay; check wiring and installation space.
Existing PW4 / PW8 pressure recorder	Matching PW4 / PW8 configuration	These families remain listed. Confirm the complete model number, pressure range and recording period.
ET855 universal-input recorder	Application-specific selection	No direct successor verified. Specify the input signal, scaling, channel count and paper-record requirement.

Before replacing an older recorder: The newer KT8/TH8 range uses 24-hour or 7-day recording. Do not assume that an older 31-day recording option, sensor, power supply or mounting arrangement transfers to the replacement. A 6-inch chart cannot be used in an 8-inch recorder.

Compact 3-inch and 4-inch temperature recorders

The Dickson SC3 uses a 3-inch chart for temperature recording where installation space is limited. Check the selected model’s temperature range and chart requirements against the conditions being monitored.

The Dickson SL4 range, including SL4100 and SL4350, combines a 4-inch chart with a digital display. Its battery operation and selectable 24-hour or 7-day recording suit temperature monitoring applications such as refrigerators, freezers and HVAC, within the selected model’s limits.

8-inch temperature and humidity recorders

The newer Dickson KT8 and TH8 recorders combine an 8-inch circular paper chart with an LCD display and replaceable sensor technology. Configurations include single or dual temperature channels, combined temperature and humidity measurement, audible alarms and selected relay-equipped models.

For remote measurements, specify the probe location, cable length and environmental conditions around the recorder itself. The sensor’s measurement range and the recorder’s permitted operating conditions must both suit the installation.

Older Dickson 8-inch temperature and humidity chart recorder models

Older 8-inch models shown for identification. Replacement models may differ in appearance and specification.

Identifying an older 6-inch recorder

Existing users of KT6 and TH6 recorders should provide the complete model number when requesting a replacement. Temperature-only and combined temperature/humidity versions require different replacement configurations.

Older Dickson 6-inch temperature and humidity chart recorder models

Older 6-inch models shown for existing users comparing replacement options.

Pressure chart recorders

Dickson PW4 and PW8 pressure chart recorders provide a paper history of pressure changes. The PW4 family uses a compact 4-inch chart, while the PW8 family uses an 8-inch chart.

Before ordering, specify the normal operating pressure, maximum expected pressure, recording duration, connection size and process medium. Confirm the suitability of wetted materials and any required snubber, filter or connection adaptor.

For other pressure and combined recording configurations, see the Palmer Wahl 8-inch and 12-inch pressure and temperature chart recorders. Selection depends on the application and installation requirements.

Universal-input recording and ET855 replacement

The Dickson ET855 universal-input chart recorder was designed for external transmitter signals, including selectable 0–20 mA, 4–20 mA, 0–5 V DC and 1–5 V DC inputs. Its two channels allow compatible transmitter outputs to be recorded on a circular chart.

A KT8, TH8 or PW recorder should not be assumed to replace an ET855. A suitable alternative must match the electrical input, engineering-unit scaling, channel count and required recording format.

Keep paper recording: Specify that a circular chart and physical record are essential.
Move to electronic recording: Specify the required signal inputs, data export, alarms and storage period.
Retain existing transmitters: Provide their model numbers, output signals and power requirements.

Charts, pens and replacement parts

Consumables must match the recorder model and configuration. The information below helps identify suitable items for both newer and older instruments.

Item required	Information to provide
Circular chart paper	Recorder model, existing chart part number, chart diameter, measurement scale and recording period.
Recording pens	Recorder model, required pen colour and a photograph or part number of the existing pen.
Temperature or humidity sensor	Recorder model, sensor part number, required range and cable length.
Power supply or other spare parts	Complete recorder model, serial number and a photograph of the component and its label.

Compatibility and availability for older instruments require confirmation before ordering. Charts and pens should be selected for the exact recorder configuration.

Pricing and replacement enquiries

Contact us for pricing and availability. Include the existing model number, measurement range, chart period and quantity required. For a replacement, photographs of the recorder label and current chart will help identify the appropriate configuration.

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Dickson Recorders Catalogue - (1.96M)