- AC Drives
- Industrial Communications
- PLC & I/O Cards
- Vibration Monitoring
- Automation Accessories
- Controllers & Data Acquisition
- CCTV & Security
- Safety Switches & Guard Locking
- Encoders
- Industrial Computers
- Servo Drives
- HMI Displays
- Motor Soft Starters
- Isolator & Barrier
- Pneumatic Cylinders
- Automation Software
- Machine Vision
- Robotics
Brand: Additel
Additel ADT878 Series Reference Dry Well Calibrator
Description
Reference-grade temperature in a portable block
The Additel ADT878 series is the high-accuracy dry well in Additel’s range, aimed at laboratories and instrument workshops that calibrate working standards, industrial PRTs and thermocouples. It trades the ADT875’s wider case for larger inserts (31.9 mm bore on the -160, 30.8 mm on the others) and deeper immersion of 160 to 193 mm, and it displays temperature to 0.001 C.
The three models mirror typical needs: -160 for cold work and freezer sensors, -425 for the bulk of process thermometers, and -700 for furnace and exhaust probes and for annealing PRTs.
Series features
- Set point control by reference and self-calibration of the internal sensor against your external probe.
- Optional external temperature control and a two-channel readout for RTDs and thermocouples.
- Built-in automatic PRT annealing on the ADT878-700, and an optional TPW kit on the ADT878-160.
- Full HART communicator and Quick-Push connectors on the PC option.
- Wi-Fi, Bluetooth, USB A, USB B and RJ45; eight display languages.
Reference dry well specification
| Parameter | Specification |
|---|---|
| Temperature range at 23 C | 878-160: -40 to 160 C; 878-425: 33 to 425 C; 878-700: 33 to 700 C |
| Display accuracy | +/-0.1 C (160); +/-0.2 C (425); 700: +/-0.20 C at 33 and 425 C, +/-0.25 C at 660 C |
| Stability, 30 min | 160: +/-0.005 C; 425: +/-0.010 C at 100 C, +/-0.015 C at 225 C, +/-0.020 C at 425 C; 700: +/-0.010 C at 100 C, +/-0.020 C at 425 C, +/-0.030 C at 700 C |
| Axial uniformity at 60 mm | 160: +/-0.035 C at -40 C, +/-0.020 C at 0 C, +/-0.050 C at 160 C; 425: +/-0.10 to +/-0.25 C; 700: +/-0.10 C at 100 C to +/-0.40 C at 700 C |
| Radial uniformity | 160: +/-0.01 C; 425: +/-0.025 C at 100 C to +/-0.040 C at 425 C; 700: +/-0.025 C at 100 C to +/-0.060 C at 700 C |
| Hysteresis (display sensor) | 0.025 C, 0.04 C and 0.07 C |
| Immersion depth | 160 mm (6.30 in) on the -160; 193 mm (7.60 in) on the -425 and -700 |
| Insert outside diameter | 31.9 mm (1.26 in) on the -160; 30.8 mm (1.21 in) on the others |
| Heating time | 160: 4 min -40 to 23 C, 10 min 23 to 160 C; 425: 15 min 23 to 425 C; 700: 25 min 23 to 700 C |
| Cooling time | 160: 15 min 23 to -40 C; 425: 24 min 425 to 100 C; 700: 30 min 700 to 100 C |
| Typical time to stability | 10 min |
| Resolution and units | 0.001 C; C, F and K |
| Display | 6.5 in (165 mm) colour touchscreen |
| Size and weight | 170 x 345 x 330 mm; 11.2 kg (-160), 9.7 kg (-425 and -700) |
| Power | 90 to 254 VAC, 45 to 65 Hz; 580 W (-160), 1400 W (-425 and -700) |
| Environment | Operation 0 to 50 C, 0 to 90% RH non-condensing; guaranteed accuracy 8 to 38 C; storage -20 to 60 C |
| Warranty | 1 year |
PC option readout
With the process calibrator option the reference PRT input reads a 100 ohm PRT to +/-0.005 C at -40 C, increasing to +/-0.028 C at 700 C (probe accuracy not included), and the reference resistance accuracy is quoted at 0.0025% of reading. The two device channels accept RTDs and thermocouples, and results are stored as tasks with as-found and as-left data.
Selecting a model and insert
Choose the model by the highest and lowest temperatures you must reach, then specify the insert pattern for your probe diameters. If your reference thermometer is an SPRT or a high-grade PRT, take the PC option so that the block can be controlled by that probe. Order the TPW kit only with the -160 and the annealing function is inherent to the -700.
Operation and safety notes
The manual says never to cut the power while the body is above 100 C, so let the block cool through the controller first. If the calibrator has been idle for more than 10 days, use the Dry-out function before calibrating. Do not apply more than 30 V to the inputs and do not apply voltage to the switch terminal.
Applications in Oman and the GCC
Accredited calibration laboratories, power and desalination plants, refineries and pharmaceutical or food-chain quality teams use reference dry wells to keep a working-standard chain between external certificates. The compact case helps when calibration has to be done on site.
Self-calibration and documentation
Like the 875, the 878 can run an automated calibration of its internal control sensor against an external reference, which gives a fresh traceable calibration of the control sensor without adding its long-term drift to the uncertainty. With the PC option the calibrator records tasks, snapshots and auto-step results, and the HART communicator reads, configures and calibrates compatible transmitters.
Selection and installation notes
A dry well gives good results only when the probe fits the insert closely and has enough immersion depth. Select inserts with the right bore for the sensors you calibrate, let the block stabilise at each set point, place the unit on a stable heat-resistant surface with room around it for ventilation and let it cool before it is moved. Follow the manual for the highest and lowest temperatures and the safe handling of hot inserts.
Information needed for a quotation
Send the full model code, the quantity, the delivery location in Oman or the GCC, the intended use and any accessories needed, so that the complete package can be quoted together.
Documents and supply information
The manufacturer data sheet is attached to this page and should be read together with the project specification and the site risk assessment before a purchase is confirmed. Ratings, standards and dimensions are quoted as printed on that sheet. Lead time, stock position and certificates available with the shipment are confirmed in the quotation, and we supply to Oman and the wider GCC region for industrial, utility and building services projects.
Related items
Inserts, secondary PRT probes and cases are listed in the datasheet accessories. See temperature calibration equipment for related instruments. Tell us the model, insert and option list and we will quote; confirm the exact code before ordering.
Datasheets & Documents
- Datasheet Additel 878 reference dry well calibrators datasheet Download
Reviews (0)
About brand
Additel is an American manufacturer of pressure and temperature calibration equipment, headquartered in Brea, California, where it also runs an NVLAP-accredited calibration laboratory. Its range covers automated pressure calibrators and controllers, documenting process calibrators, digital pressure gauges, test pumps and dry well calibrators. Additel has offices in Utah, Beijing and Odense, Denmark, and its products are used in more than 100 countries.
Seven Star LLC is an independent supplier in Muscat. We list Additel instruments with their official datasheets for instrument and calibration teams in oil and gas, power, water and manufacturing in Oman and the GCC.
Additel company profile
| Headquarters | Brea, California, USA |
|---|---|
| Calibration laboratory | NVLAP-accredited, Brea |
| Other offices | Pleasant Grove (Utah), Beijing and Odense (Denmark) |
| Reach | Products used in more than 100 countries |
| Product families | ADT760A and ADT761A automatic handheld pressure calibrators, ADT762 hydraulic calibrator, ADT226 documenting process calibrator, ADT681A and ADT601Ex digital pressure gauges, ADT875 dry well calibrators, pressure test pumps |
Additel product series
Pressure calibration equipment includes the ADT760A and 760S automatic handheld pressure calibrators, the ADT761A portable automatic calibrator, the ADT762 automated hydraulic calibrator and the ADT927 hydraulic test pump for 700 bar. Digital pressure gauges include the ADT681A wireless gauge with accuracy up to 0.01% of full scale and the ADT601Ex intrinsically safe gauge.
The ADT226 is a multifunction documenting process calibrator, and the ADT295 communicates with HART, Foundation Fieldbus and Profibus PA devices. Temperature calibration is covered by the ADT875 dry well calibrators and the ADT878 reference dry well calibrators.
Where Additel instruments are used
Field calibration of pressure and temperature transmitters, gauges, switches and RTDs, loop checks and documented calibration for quality audits, and calibration labs in plants and service companies.
Additel products we list
Ordering Additel instruments: what we need
Send the model and pressure range, the medium (gas, oil or water), accuracy class and whether results must be documented. For dry wells give the temperature range, stability and insert size. We confirm the exact model code before ordering.
Facts checked against Additel's own catalogue and calibration services brochure, October 2026.
Browse Additel products by category: Portable Test & Measurement, Pressure Instrumentation.
Related products
Frequently Asked Questions
Which models make up the ADT878 series?
ADT878-160 (-40 to 160 C), ADT878-425 (33 to 425 C) and ADT878-700 (33 to 700 C), each with an optional process calibrator (PC) version.
Why is it called a reference dry well?
The datasheet quotes display accuracy down to +/-0.1 C and stability down to +/-0.005 C, which is higher performance than its sibling ADT875 series.
What are the model-specific options?
An optional TPW kit for built-in automatic triple-point-of-water realization exists for the ADT878-160 only, and automatic PRT annealing is built into the ADT878-700 only.
What does the PC option add?
An external reference input, a two-channel readout for devices under test (RTD and thermocouple), documentation tasks and a full HART communicator, with Quick-Push connectors.
What should I watch for when switching it off?
The manual says not to cut the power while the body is above 100 C, and to run Dry-out for over 10 days of non-use. Do not apply voltage to the switch terminal.
Reviews
There are no reviews yet.