5 Reasons Why Installing a Monitoring Sensor Through a Door Gasket Is a Bad Idea

Why the designated pass through port should always be preferred over improvising with the door gasket

The XiltriX monitoring system is renowned for its precision, reliability, and safety in monitoring critical parameters such as temperature, humidity, and CO₂ concentrations in laboratories, refrigerators and freezers, cleanrooms, and other controlled environments. A crucial part of installing XiltriX sensors lies in the correct placement of measurement cables and sensors. Unfortunately, users too often attempt to simplify installation by running a sensor through the door gasket instead of using the device’s dedicated pass through port. Although this may seem like a quick fix at first, it is risky and can seriously compromise the accuracy, safety, and longevity of both the device and the monitoring system. In this blog post, we share five important reasons why this practice should be avoided and why the pass through port is always the right choice.

1. Creation of a hot/cold spot

One of the main reasons devices like incubators, refrigerators and freezers are equipped with a pass through or access port is to provide a way to install sensors properly in the device. Door gaskets are specifically designed to seal airtight. When a sensor or cable is forced between the gasket and the device, it creates a tiny opening in the seal. This allows warm air to enter and cold air to escape, potentially causing temperature fluctuations inside the device. This is not only detrimental to products that must be stored under ideal conditions, such as biological samples, pharmaceuticals, or chemicals, but it also makes the device work harder to maintain the set temperature. This leads to more wear and increased energy consumption.

Additionally, moisture from the outside air can enter through this opening, resulting in increased humidity inside the device. This can affect measurement results and also cause ice formation (in freezers) or condensation, which further undermines the device’s effectiveness.

2. Contamination hazard

Another crucial reason to avoid installing a sensor through the door gasket is the risk of contamination. When the door no longer seals completely airtight, even the smallest gap allows for unwanted exchange of air and particles between the interior and exterior of the device. In sensitive environments such as laboratories or pharmaceutical storage rooms, these tiny openings can let in dust, microorganisms, fungi or other contaminants. As a result, samples or products may be exposed to non-sterile conditions, jeopardizing not only the integrity of the stored materials but also the reliability of research results.

3. Damage to Door Gasket and Sensor

The door gasket is a vital component; it ensures an airtight seal and helps prevent energy loss. Clamping a cable or sensor behind the door gasket constantly compresses the gasket and may eventually deform or even tear it. This leads to permanently reduced sealing, even if the sensor is later removed. Ultimately, the gasket may need to be replaced, incurring high costs and rendering the device temporarily out of use.

The sensor or cable itself can also become damaged. Due to the pressure from the gasket and the frequent opening and closing of the door, the cable sheath may become damaged, leading to short circuits or measurement malfunctions. Moreover, cable kinking can drastically shorten the sensor’s lifespan.

4. Unreliable Measurement Results

If the sensor or cable is not routed through the official pass through port, the measurement environment can be affected by external factors. The door gasket method increases the risk of temperature fluctuations, humidity changes, and even contamination of the measurement chamber. This leads to unreliable data, meaning the sensor may no longer meet requirements for accreditations, quality standards (such as ISO 17025), or Good Laboratory Practice (GLP).

Unreliable measurements can have serious consequences, especially when the monitoring system is meant to trigger alarms in case of deviations. Think of false alarms due to apparent temperature loss, or missing a real incident because the data is no longer accurate. In laboratory or healthcare settings, this can result in the loss of valuable samples or even compromise patient safety.

5. Excessive Gas Consumption and Sample Damage

A leak in the door gasket can have significant implications for low oxygen CO₂ incubators that rely on Nitrogen gas to maintain precise atmospheric conditions. In these systems, Nitrogen is introduced to displace oxygen, creating the hypoxic environment required for cell cultures. However, when the gasket fails to maintain an airtight seal, the incubator’s internal atmosphere becomes unstable. The constant inflow of Nitrogen not only pushes out Oxygen but also drives out other critical components of the environment, including carbon dioxide (CO₂) and humidity.

CO₂ is often deliberately added to incubators to support cell metabolism and maintain pH balance in culture media. Humidity, meanwhile, is crucial for preventing evaporation and keeping cells hydrated. With a compromised gasket, the Nitrogen used to purge Oxygen escapes more rapidly, taking CO₂ and moisture along with it. This creates a vicious cycle: the more the incubator leaks, the more Nitrogen must be supplied to maintain low Oxygen levels, resulting in excessive gas consumption and operational inefficiency.

As CO₂ and water vapor are expelled, the incubator’s internal humidity drops, causing the culture medium to evaporate. Over time, this drying effect can stress or even kill sensitive cell cultures, undermining experimental outcomes and wasting precious biological material. Maintaining a tight seal is therefore essential—not only for preserving gas concentrations but also for safeguarding the delicate balance of humidity required for healthy cell growth.

Conclusion

Although it may seem tempting to quickly place a sensor behind a door gasket, the risks and disadvantages far outweigh any time saved. Properly routing sensors through the official pass through port is essential for maintaining reliable measurement results, the device’s durability, and compliance with quality standards. When access ports are not in available, XiltriX engineers can make access ports for selected types of devices. Always choose quality, safety, and professionalism—even if installation takes a bit more time.

At XiltriX we don’t do things fast, we do things right!