Thermo Scientific Precision 280

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Overview

Important Technical Specifications
Usage Features
Maintenance Features

This document is an installation and operation manual for microprocessor-controlled general-purpose water baths, specifically covering Models 280 (2825/2826), 281 (2829/2830), 282 (2833/2834), 283 (2837/2838), 284 (2841/2842), 285 (2845/2846), 286 (2849/2850), and 288 (2853/2854). The manual provides comprehensive information for safe and satisfactory operation, including an introduction, unpacking and damage instructions, general information, performance data, installation guidelines, explanation of controls, operation procedures, maintenance, troubleshooting, parts replacement, replacement parts list, assembly and schematic drawings, and warranty information.

The water baths are designed for research and quality control applications, offering superb temperature uniformity and stability, making them suitable for legal or reference tests. The interior of the bath is constructed of stainless steel, designed for operation with distilled water or water solutions, such as water ethylene glycol with corrosion inhibitors. The body is made from galvanized steel and painted for added protection. A gable cover is provided with the bath, which is required to maintain optimal temperature sensitivity and achieve maximum performance.

Important Technical Specifications:

The manual lists various models with their electrical characteristics and capacities.

Electrical Characteristics:
- 120V Models:
  - 280 (2825): 225 Watts, 1.9 Amps
  - 281 (2829): 225 Watts, 1.9 Amps
  - 282 (2833): 300 Watts, 2.5 Amps
  - 283 (2837): 400 Watts, 3.3 Amps
  - 284 (2841): 600 Watts, 5 Amps
  - 285 (2845): 600 Watts, 5 Amps
  - 286 (2849): 1200 Watts, 10 Amps
  - 288 (2853): 800 Watts, 6.7 Amps
- 240V Models:
  - 280 (2826): 225 Watts, 1 Amp, Mains Fuse FST-5x20-1.0A
  - 281 (2830): 225 Watts, 1 Amp, Mains Fuse FST-5x20-1.0A
  - 282 (2834): 300 Watts, 1.3 Amps, Mains Fuse FST-5x20-2.0A
  - 283 (2838): 400 Watts, 1.7 Amps, Mains Fuse FST-5x20-2.0A
  - 284 (2842): 600 Watts, 2.6 Amps, Mains Fuse FST-5x20-3.15A
  - 285 (2846): 600 Watts, 2.6 Amps, Mains Fuse FST-5x20-3.15A
  - 286 (2850): 1200 Watts, 5.2 Amps, Mains Fuse FST-5x20-6.3A
  - 288 (2854): 800 Watts, 3.5 Amps, Mains Fuse FST-5x20-3.15A
  - For all 240V models, the Power Supply Board Fuse is FST-5x20-6.3mA.
Capacity:
- 280 (2825/2826): 1.5 Liters, 0.4 Gallons
- 281 (2829/2830): 2.5 Liters, 0.7 Gallons
- 282 (2833/2834): 5.5 Liters, 1.5 Gallons
- 283 (2837/2838): 12.0 Liters, 3.2 Gallons
- 284 (2841/2842): 19.5 Liters, 5.2 Gallons
- 285 (2845/2846): 18.0 Liters, 4.9 Gallons
- 286 (2849/2850): 43.0 Liters, 11.4 Gallons
- 288 (2853/2854): 12.0* Liters, 3.2* Gallons (*Each chamber)
Performance Data (with gable cover in place):
- Control sensitivity @ 37°C: ±0.1°C
- Temperature uniformity @ 37°C: ±0.2°C
- Minimum bath temperature: Ambient +5°C
- Maximum bath temperature: Not specified, but operation up to 100°C is mentioned.
- Maximum performance is assured across the following temperature range: 15°C to 45°C.
Environmental Conditions:
- Indoor Use Only
- Temperature: 5° to 40°C
- Maximum Relative Humidity: 80% for temperatures to 22°C
- Maximum Altitude: 2000 meters

Usage Features:

Microprocessor Control Panel: Houses all functions, including a digital readout for temperature, a "Heater On" indicator, and push-button keys for user selections.
LED Display: Three digits display actual, set, and calibrated temperature values.
Heater On Lamp: Illuminates when power is applied to the heater.
Calibrate Key: Puts the unit in calibrate mode to match a traceable thermometer to the actual temperature display.
Temperature Selection Keys (Up/Down Arrows): Used to increase or decrease the setpoint and/or calibrate temperature selections.
Enter Key: Used to store a new setpoint or calibration value.
Proportional Integral Derivative (PID) Temperature Control: Allows precise temperature control.
High Limit Temperature Cutout: Provided for safety in case of an empty water bath. If the sensor reads 5°C higher than the set temperature, a cutout occurs, indicated by "EEE" on the display, and the heater is inhibited. To reset, power must be cycled off and on. This cutout is internally set and not user-adjustable.
Installation: Place on a level surface away from drafts. The stainless steel diffuser pan (shelf) should be placed inside the bath chamber, corners facing downward, to provide a sample base and protect samples from the hot bath bottom. A Leg Extension Kit is included (except for Model 2829/2830) to increase diffuser pan height if needed.
Electrical Connection: Units are equipped with a three-prong (grounding) plug. Users are warned against cutting the third prong or using two-prong adapters. It is critical to ensure the wall receptacle provides adequate current and is properly grounded.
Filling the Bath: Use distilled water only. The acceptable resistivity range is 50K to 1M ohms (conductivity 1 to 20 micro Siemens), and the pH range is 7 to 9. Using chlorinated tap water, additives containing chlorine, or high-purity deionized water outside the specified range will void the manufacturer's warranty. The maximum liquid level is 1 inch below the top of the pan to allow for sample displacement.
Operation:
- Power up by depressing the power switch. The display will show all segments, then the current set temperature for 5 seconds, then the actual bath temperature.
- To display the set temperature, quickly press the Up or Down key.
- To change the set temperature, continuously press the Up or Down key until the desired temperature is displayed, then press ENTER. The new set temperature will flash three times.
- Calibration: Place a certified thermometer in the holder and allow it to stabilize for at least 15 minutes. Press the CALIBRATE key. While the display flashes, use the Up or Down keys to match the thermometer reading, then press ENTER.

Maintenance Features:

Stainless Steel Care: Stainless steel resists corrosion but requires care. Regular cleaning with mild soapy water or a non-scratching scouring powder is sufficient.
Algae/Microorganism Control: Add a small amount of formaldehyde or zephiran chloride to the bath media if algae or other undesirable microorganisms form.
Chemical Spills: Exercise care when using acidic or caustic solutions. If spills occur, immediately drain the bath, thoroughly flush the unit, and clean/remove spills and condensation from all metal surfaces after each use.
Electrolysis Prevention: Do not allow objects to rest directly on the stainless steel surface, as this can trap moisture and lead to pitting or erosion due to electrolytic action.
Alternative Media: If using media other than water, limit use to a maximum of four hours and clean surfaces immediately afterward.
Prohibited Chemicals: Never use Aqua Regia, Ferric Chloride, Iodine, Sodium Azide, or Sulfuric Acid.
Rust Removal: If stainless steel discolors with iron rust, prepare a solution of 20% nitric and 1.5% hydrochloric acid (or 2-5% warm oxalic acid). Swab the solution over the surface for 1-2 minutes until rust loosens, then flush thoroughly with clean water and dry.
Condensation Management: When removing the gable cover, center one corner over the bath to direct water runoff into the bath. Shake the cover to aid runoff and wipe up any spillage.
Decontamination: The user is responsible for appropriate decontamination if hazardous material is spilled on or inside the bath.
Troubleshooting: The manual provides detailed troubleshooting procedures for common issues like "No Heat," "Unstable temperature control," "Too much heat," and "No Display," including steps to check the temperature probe, heater, TRIAC, and fuses.
Parts Replacement: Instructions are provided for replacing the temperature sensor, heater, and control board. Specific cautions are given for control board replacement regarding jumper settings for 120V and 240V models.