Memmert UN750 Universal Oven, large-capacity heating and drying oven with natural convection, 749 litres, up to 300 °C

With an internal volume of 749 litres, the Memmert UN750 universal oven is the largest natural convection model in the entire UN series and, with up to 14 shelves, offers space for significantly more parallel batches than any smaller model in the range. Like all UN models, it does not feature a forced-air fan and operates purely by natural convection within a temperature range of 20 to 300 °C. For businesses with high sample throughput in multi-shift operation, such as in industrial materials testing or quality assurance, the UN750 represents the upper limit of the capacity offered by the natural convection series.

Natural convection in the largest size of the series

Even with an internal volume of 749 litres and 14 possible shelves, the Memmert UN750 universal oven deliberately does without an air turbine and a recirculation fan. Heat rises purely by convection, without a fan stirring up dust or light sample particles – an advantage that is particularly evident when so many levels are occupied simultaneously. The operating temperature range extends from at least 5 °C above room temperature up to 300 °C. A Pt100 temperature sensor of DIN Class A in a 4-wire configuration provides a setting accuracy of 0.1 °C up to 99.9 °C and 0.5 °C from 100 °C onwards, regardless of the number of shelves in use.

ControlCOCKPIT SingleDISPLAY and three-phase connection for high utilisation

The UN750 is operated via the ControlCOCKPIT SingleDISPLAY, an adaptive, multifunctional digital PID microprocessor controller with a TFT colour graphic display. Temperature, exhaust air damper position, programme duration, time zone and summer/winter time can all be set. A digital countdown timer ranging from 1 minute to 99 days and the SetpointWait function, which only starts the process time once the setpoint temperature has been reached, ensure reproducible results even during continuous multi-shift operation. Due to the required heating power, the UN750 is operated with 400 V three-phase current and 3 x 230 V without a neutral conductor at 50/60 Hz and approximately 7,000 W. The data logger can be read via the Ethernet interface; a time-limited trial version of the AtmoCONTROL software is available for download.

Capacity of the Memmert UN750 universal chamber

The internal dimensions are 1,040 x 1,200 x 600 mm, whilst the external dimensions of the cabinet are 1,224 x 1,720 x 784 mm. It can accommodate up to 14 shelves – more than any other model in the UN series – and two electropolished stainless steel wire shelves are included as standard. The UN750 has a total load capacity of up to 300 kg, with a maximum load of 30 kg per shelf. The interior consists of easy-to-clean stainless steel, reinforced with deep-drawn ribbing, featuring protected, integrated 4-sided all-round heating; the cabinet is made of textured stainless steel with a fully galvanised sheet steel rear panel. The fully insulated stainless steel doors are secured by a 2-point locking mechanism with a compression door latch.

Selection guide: the top of the natural convection range

The Memmert UN series with natural convection ranges from 32 to 749 litres in internal volume. The UN750 shares the same footprint as the UN450, but is around 47 cm taller and therefore offers almost twice as many shelves.

If there is insufficient headroom at the installation site for the UN750’s 1.72 m overall height, the Memmert UN450 universal cabinet—with the same footprint but a significantly lower height—is the practical alternative. For smaller batch sizes, the Memmert UN260 universal cabinet with a capacity of 256 litres is often sufficient. The full range can be found under Climate Cabinets & Incubators.

Distinction: natural convection versus forced air circulation

With a capacity of 749 litres and 14 shelves, the question of active air circulation often arises. Forced-air models in the UF series feature an electronically controlled fan, which actively distributes heat throughout the interior, thereby achieving shorter heating times for densely packed batches of varying sizes – though only from 10 °C rather than 5 °C above room temperature. For large quantities of material samples that are sensitive to dust or vibration, the natural convection of the UN750 remains the more technically suitable choice. A forced-air model of a comparable size, albeit smaller, is the Memmert UF450 universal oven with a capacity of 449 litres. Like all standard models in the series, the UN750 uses the ControlCOCKPIT SingleDISPLAY, rather than the TwinDISPLAY, which is reserved for the ‘plus’ variants.

Safety in accordance with DIN 12880 at high utilisation

With up to 14 trays occupied simultaneously and processes that often run overnight or for several days, reliable process safety is essential. The UN750 features adjustable electronic temperature monitoring plus a mechanical temperature limiter of protection class 1 in accordance with DIN 12880, which switches off the heating when the temperature reaches approximately 20 °C above the maximum cabinet temperature. A self-diagnostic system assists with fault-finding, and 3 freely selectable temperature values can be calibrated. The unit bears CE and EAC markings as well as a UL mark.

Installation, operation and disposal

The same clearance requirements apply during operation as for the smaller models in the series: a minimum of 15 cm clearance from the wall, a maximum of 20 cm clearance from the ceiling, and a minimum of 5 cm clearance to the side from a wall or adjacent unit. With a height of 1.72 m and a net weight of around 217 kg, the room height at the installation site should be checked in advance and a high-voltage connection for three-phase operation should be provided. Installation is permitted at altitudes of up to 2,000 m above sea level, at ambient temperatures between 5 °C and 40 °C and with a maximum relative humidity of 80 per cent, non-condensing. Electrically, the UN750 is designed for overvoltage category II and pollution degree 2; it must only be transported in an upright position. As an electrical appliance, the UN750 is subject to the Electrical and Electronic Equipment Act at the end of its service life and must not be disposed of with household waste.

Typical applications

With an internal volume of 749 litres and up to 14 shelves, the Memmert UN750 universal cabinet offers the highest throughput of the entire UN series.

• Heat treatment of very large material batches in industrial multi-shift operation
• Standard annealing, ageing and curing of numerous material samples in parallel
• Material testing and quality assurance with maximum sample throughput
• Vibration-free heat treatment of dust-sensitive materials on a large scale
• Central heat treatment station for multiple production lines

Investment rationale: optimising capacity utilisation

The UN750 is supplied with 2 electropolished stainless steel grating trays; the cabinet is designed to accommodate up to 14 trays, each with a maximum load of 30 kg. Anyone wishing to utilise the full capacity should factor in the additional grating trays or perforated sheets from the outset. For process monitoring across so many levels, a 4–20 mA current interface, fan speed monitoring, an additional Pt100 sensor and SMS alerts are available; for access control, a lockable door with a security lock is provided. In addition, we supply base frames with levelling, as well as calibration, IQ/OQ/PQ services in accordance with DIN 12880 and maintenance contracts – some of which are DAkkS-accredited – which are particularly recommended for a unit of this size.

Frequently asked questions before purchase

How many samples can the UN750 hold at once?
Up to 14 shelves, each with a maximum load of 30 kg, giving a total load capacity of up to 300 kg – more than any other model in the UN series.

What ceiling height do I need for the UN750?
The external dimensions are 1224 x 1720 x 784 mm; the height of 1.72 m should be checked against the available room height before delivery.

Why does the UN750 require three-phase power?
With a power consumption of around 7,000 W, the UN750 requires more heating power than can be reasonably supplied by a single-phase supply; therefore, it requires 400 V three-phase power and 3 x 230 V without a neutral conductor.

Is the UN750 also available with forced air circulation?
A forced-air model with a comparable control system but a smaller capacity is the Memmert UF450 universal cabinet, which has a capacity of 449 litres and an electronically controlled fan.

What is the accuracy of the temperature control?
Even in the largest model in the series, it remains unchanged: 0.1 °C up to 99.9 °C and 0.5 °C from 100 °C, via a DIN Class A Pt100 sensor using 4-wire technology.

Is the UN750 suitable for continuous operation in a multi-shift system?
The mechanical temperature limiter, which complies with Protection Class 1 according to DIN 12880, switches off the heating element at an overtemperature of approximately 20 °C and is designed for long, unattended processes.

Technical details

Contents of delivery

• 1x Memmert UN750 universal cabinet
• Factory calibration certificate (calibrated at 160 °C)
• Fully insulated stainless steel doors with 2-point locking (compression door seal)
• 2x stainless steel grating, electropolished

Regulatory information

The Memmert UN750 universal cabinet is registered with the Stiftung Elektro-Altgeräte Register (Stiftung EAR) under WEEE registration number DE 66812464.

Customised requirements & procurement service

Options available for the UN750 include a lockable door with a security lock, a gas-tight version with various pipe penetrations, and reinforced grating and perforated sheets. For process monitoring, a 4–20 mA current interface, fan speed monitoring, an additional Pt100 sensor and SMS alerting are available. In addition, we supply base frames with levelling, as well as calibration, IQ/OQ/PQ services in accordance with DIN 12880 and maintenance contracts. Do you require any of these accessories or assistance in selecting the right universal cabinet for your application? Through our procurement service, LT Laborhandel will be happy to assist you with procurement and configuration.