MEMMERT WNB14 Water Bath Circulator

Overview

The MEMMERT WNB14 Water Bath Circulator is a precision-engineered, German-manufactured thermostatic bath designed for reliable, reproducible temperature control in laboratory environments requiring stable thermal conditions over extended periods. Based on resistive heating and forced internal recirculation, the WNB14 maintains uniform temperature distribution across its 14 L stainless steel bath chamber using a high-efficiency circulation pump and a four-wire Pt100 sensor system—ensuring traceable, NIST-traceable-compatible temperature measurement with minimal self-heating error. Unlike passive water baths, the WNB14’s active circulation minimizes thermal stratification and accelerates equilibration time, making it suitable for applications demanding tight thermal tolerance—such as enzyme kinetics assays, cell culture incubation support, solvent evaporation, and controlled hydrolysis reactions. Its robust architecture complies with IEC 61010-1 safety standards for laboratory electrical equipment and meets electromagnetic compatibility requirements per EN 61000-6-2 (immunity) and EN 61000-6-3 (emission).

Key Features

• Precision temperature control via PID algorithm with dual (B-type) or triple (E-type) independent overtemperature protection circuits—including electronic fail-safe cutoff (ΔT = +10 °C above setpoint), user-configurable electronic limit (TWW/TWB), and mechanical backup (TB, activated at +30 °C above bath rating)
• Four-wire Pt100 resistance thermometer (standard on E-type; single probe on B-type) ensures measurement accuracy of ±0.1 °C at 37 °C under no-load conditions
• LED display with intuitive menu navigation, real-time alarm status indication, and self-diagnostic functionality for heater, sensor, and circulation system integrity
• Programmable timer with up to 999 hours runtime (E-type) or 99 h 59 min (B-type); supports Start, Delayed Start, Hold, and Time-Dependent Hold modes for unattended operation
• Stainless steel AISI 304 bath and housing—resistant to corrosion from water, mild aqueous solutions, and common organic solvents; seamless interior welds prevent microbial trapping
• Boiling mode enables rapid transition to 100 °C for sterilization or solvent removal without manual override

Sample Compatibility & Compliance

The WNB14 accommodates standard laboratory glassware including Erlenmeyer flasks (100–500 mL), test tubes (14.5–32 mm diameter), and reaction vessels up to 350 × 290 mm footprint. Optional accessories—including flat and gabled lids, orbital shaker modules (WB-only), adjustable-height stands, conical flask clamps, and multi-position tube racks—extend operational flexibility while maintaining thermal uniformity. The unit conforms to GLP-relevant design principles: all temperature and timer settings are non-volatile, and event logs (e.g., overtemperature events, power interruptions) are retained in memory. While not inherently 21 CFR Part 11 compliant, the E-type controller supports external data logging via RS232/USB interface, enabling integration into validated systems when paired with compliant software and audit trail protocols.

Software & Data Management

The WNB14 operates autonomously via its embedded microcontroller and does not require proprietary PC software for basic function. However, the E-type model includes an RS232 port (with optional USB adapter) for remote parameter readout, real-time temperature streaming, and event-triggered logging. Third-party SCADA or LIMS platforms can acquire timestamped temperature data at user-defined intervals (1–60 s). Firmware updates are performed via serial connection using MEMMERT’s standardized protocol; version history and calibration certificates are stored internally and retrievable via service menu. No cloud connectivity or wireless transmission is implemented—ensuring data sovereignty and alignment with institutional IT security policies.

Applications

• Controlled enzymatic digestion and protein denaturation studies requiring ±0.2 °C stability over 8+ hour durations
• Support incubation of microbiological media prior to pour plating or broth enrichment
• Constant-temperature solvent evaporation in analytical sample preparation (e.g., LC-MS extract concentration)
• Thermal conditioning of viscometry standards and reference oils per ASTM D445
• Pre-warming reagents for immunoassays and nucleic acid hybridization protocols
• Calibration verification of handheld thermometers and infrared sensors against traceable bath references

FAQ

Is the WNB14 suitable for oil bath operation?
Yes—the WNB14 platform supports both water and silicone oil (up to 100 °C); however, oil use requires the OB14 variant housing with enhanced sealing and thermal insulation. Standard WB14 units are optimized for aqueous media.
What is the maximum recommended fill level for optimal circulation?
For uniform flow and minimal surface turbulence, maintain liquid level between 80–100% of nominal volume (i.e., 11.2–14 L). Overfilling may impair pump efficiency and increase risk of overflow during thermal expansion.
Can the WNB14 be integrated into a networked lab infrastructure?
It supports point-to-point serial communication only. Network integration requires external hardware (e.g., RS232-to-Ethernet converter) and middleware compatible with Modbus RTU or ASCII command sets.
Does MEMMERT provide factory calibration documentation?
Each unit ships with a DIN EN ISO/IEC 17025-accredited calibration certificate (traceable to PTB) for the primary Pt100 sensor, valid for 12 months from date of manufacture.
Are replacement parts available globally?
Yes—genuine MEMMERT spare parts (pumps, heaters, sensors, lids) are distributed through authorized partners in >80 countries, with lead times typically ≤5 business days for in-stock items.