A laboratory oven is a critical component in various research and testing processes, and it is imperative to keep it in optimal condition to avoid compromising the quality of data produced or the safety of those who operate it. Routine maintenance practices can help extend the lifespan of the oven, prevent breakdowns, and ensure optimal performance. Following best practices for maintaining a laboratory oven will help you keep your oven running smoothly and efficiently while avoiding costly repairs and replacements.
Cleaning is the first step in all laboratory equipment maintenance and can prevent many costly repairs. Cleaning frequency should be determined based on your oven usage. Make sure to prioritize safety when cleaning your laboratory oven by switching it off and allowing it to cool completely before cleaning.
While you should refer to your laboratory oven’s operating manual and relevant laboratory safety guidelines, here is an example of a checklist for cleaning your laboratory oven:
- Ensure that the oven is turned off, unplugged, and completely cooled before beginning any cleaning.
- Decontaminate the work area and wipe down the exterior as needed before interior cleaning. Don’t spray the display directly with cleaner.
- If you use hazardous chemicals in your lab oven or are unaware of the chemicals used, wear appropriate protective gear, such as gloves and safety goggles, during the cleaning process to protect yourself from any hazardous residuals inside your oven.
- Remove any shelving or other removable accessories. Remove any loose debris or residue from the oven's interior using a soft brush or cloth.
- Wipe the oven's interior surfaces thoroughly with a mild detergent or cleaning solution and a soft cloth. Mild soap and water or isopropyl alcohol (99%) are recommended. Do not use chlorine-based cleaners or abrasive materials that could damage the oven. If working with contaminants, use a non-abrasive disinfectant.
- Using a sponge or cloth, rinse the interior of the oven thoroughly with clean water to remove any remaining cleaning solution or residue.
- Dry the interior of the oven with a soft cloth or paper towel.
- Replace any parts or accessories removed during the cleaning process, such as shelves or racks.
- Dispose of cleaning materials according to laboratory safety protocols.
Refer to the user manual for guidance on how often to perform preventative maintenance. Whether you delegate these to a lab member or maintenance staff at your institution or bring in an expert for regular inspection, it is a good idea to have a written, communicated maintenance schedule.
The type of laboratory oven and the ways in which it is used will determine the necessary maintenance. Two common types of laboratory ovens are convection and vacuum ovens. Convection ovens can be either forced-air thermal convection or gravity convection ovens.
A forced-air thermal convection oven uses a fan to circulate hot air throughout the oven chamber, creating a uniform temperature and ensuring even heating. They can often handle larger sample volumes and are useful for applications that require rapid heat-up and cool-down times. Gravity convection ovens rely on gravity to create a uniform temperature environment and are considered more efficient than forced-air convection ovens. By comparison, a vacuum oven operates under reduced atmospheric pressure. It can be used for applications such as drying, degassing, and curing materials sensitive to heat, moisture, or oxygen. The reduced pressure in the oven chamber lowers the boiling point of water, allowing for faster drying of samples at lower temperatures.
Maintenance is pretty minimal for most laboratory ovens. Vacuum ovens will additionally require regular pump maintenance (discussed below). For all laboratory ovens, you’ll want to periodically:
- Check for loose or damaged wiring. (If observed, contact a service provider and discontinue use)
- Visually inspect for damage, such as that caused by heat or liquids. (If observed, contact a service provider and discontinue use)
- Remove any dust or other debris that has accumulated at the intake vent.
There are several different vacuum pumps used with vacuum lab ovens, including diaphragm pumps, rotary vane pumps, scroll pumps, and diaphragm-rotary vane hybrids. Pumps should undergo maintenance annually, or more frequently based on your usage. Refer to the user manual for your particular model as the maintenance varies widely among pump types. You may want to outsource pump maintenance to a service professional.
- Replace seals and diaphragms (if applicable) annually. (or more frequently with heavy use or damage)
- Regularly check oil levels (if applicable)
- Perform an oil change whenever the oil darkens (if applicable)
- Regularly check the filter trap or oil mist separator for any clogs or debris. If using a cold trap, make sure it is emptied after each use.
- Check tubing for any defects and replace as needed
Door gaskets are the most likely components to wear out and need to be replaced over time.
- Check the door latch, trim, catch, and gasket to ensure a proper seal.
- Inspect the silicone gasket for cuts, nicks, cracks, and brittleness.
- For ovens that use fiberglass gaskets, check for proper placement as well as any visual damage and replace as needed.
Some oven manufacturers suggest the gaskets within the door and frame be replaced annually, but this should be decided based on the condition of your oven gaskets. A torn door gasket can impede temperature uniformity as well as shorten the lifespan of the oven.
Most ovens use silicone gaskets while others use gaskets made from fiberglass. You can order a replacement gasket directly from the manufacturer or we offer replacement gaskets for several models. The user manual for your model will describe how to replace the gasket. Here is an example of the replacement protocol for the CVO-10 Vacuum Oven as described in the user manual:
Accurate oven temperatures are crucial for numerous laboratory processes. Although temperature controls and safety mechanisms are usually dependable, regularly checking your laboratory oven's calibration will indicate if the oven is attaining the appropriate temperatures for your applications.
- Insert a calibrated thermocouple probe into the oven chamber and place it as close to the center as possible. For a vacuum oven, this will be fed in through a vacuum-rated feedthrough port, while for a convection oven, it can be fed in through an intake vent or access port.
- Close and latch the door, ensuring a proper seal. Begin your program.
- The oven will heat up. Wait for the temperature to stabilize for accurate calibration. This will take approximately 30 minutes for a convection oven and an hour for a vacuum oven.
- If the readings on your probe and display match or are within an acceptable range, the calibration is complete. If they are significantly different, you’ll need to recalibrate the display. Refer to your operational or user manual for guidance on how to recalibrate the display.
Inspect Electrical Components
It is a good idea to visually inspect any visible electrical components for signs of damage or failure. Also, monitor the operation of safety features when in use, to make sure interlocks and sensors are working properly. However, electrical failures should be handled by professionals. Refer to your user manual or contact the manufacturer for service.
For specific examples of lab oven maintenance, see these user manuals and resources for vacuum and forced-air ovens: