In this guide, you will learn what to consider when selecting, installing and using a condensation monitor.
What is condensation and when does it occur?
Condensation occurs when humid air comes into contact with a significantly colder surface. The air can then no longer retain all of the water vapour it contains. Water settles on the surface in the form of moisture. This process is known as condensation or surface condensation.
Condensation occurs particularly often on cold water pipes, cooling pipes, chilled ceilings and other components with a low surface temperature. Early condensation monitoring helps to detect critical humidity levels and initiate suitable countermeasures in good time.
What is a condensation monitor?
A condensation monitor is a monitoring device that records the relative humidity and temperature in the area of a surface at risk. This enables the device to detect when the ambient conditions are approaching a critical state for condensation formation.
The condensation monitor switches the integrated changeover contact when the fixed switching point of approximately 93 % relative humidity is reached. The output signal can be connected to a higher level control system in order to activate a heater, pump or other actuator, for example.
What are condensation monitors used for?
A condensation monitor is used wherever cold surfaces or technical components need to be protected from moisture. It is particularly suitable for applications where a direct switching signal is required.
Typical applications include:
- Cold water pipes and cooling pipes
- Chilled ceilings and cooled surfaces
- Ventilation and air conditioning systems
- Building automation
- Technical plant rooms and service areas
- Control cabinets and technical enclosures
- Industrial systems and production areas
- Moisture sensitive components and system areas
By detecting critical humidity levels at an early stage, connected control and regulation systems can respond in good time. This helps to reduce the risk of condensation and the resulting moisture damage.
How does a condensation monitor work?
The condensation monitor uses a digital humidity sensor with an integrated temperature sensor. The sensor records the conditions in the area of the monitored surface and transmits the measured values to the device electronics.
The switching point is fixed at approximately 93 % relative humidity. If this value is exceeded, the condensation monitor detects a critical humidity level and switches the changeover contact. The connected control system can then initiate suitable measures to prevent condensation.
The changeover contact enables flexible integration into control and monitoring systems. Depending on the connection, it can be used to control or monitor other system components. The connection assignment of the relevant model must be observed.
Which designs of condensation monitors are available?
Our condensation monitors are available in two designs. Both versions feature a changeover contact, a fixed switching threshold of approximately 93 % relative humidity and IP65 protection. The main difference is the installation method and the positioning of the sensor.
What are the advantages of a condensation monitor?
A condensation monitor provides a simple way of detecting critical humidity levels on cold surfaces at an early stage. Unlike a temperature sensor alone, it also monitors relative humidity. This allows the risk of condensation to be assessed more effectively.
The integrated changeover contact provides a directly usable switching signal. This means that the condensation monitor can be integrated into many control and monitoring systems without an additional output module.
- Fixed switching point of approximately 93 % relative humidity
- Monitoring of relative humidity and temperature
- Direct control of connected actuators
- Choice between direct installation and an external circuit board
- Robust design with IP65 protection
- Simple electrical connection via screw terminals
How do I select the right condensation monitor?
When selecting a condensation monitor, the installation situation should be considered first. If the monitored surface is easily accessible, the version for direct installation with a mounting block and mounting strap is suitable. If space is limited or the measuring point is difficult to access, the version with an external circuit board and flexibly positionable sensor is recommended.
The following points should also be taken into account:
- Type and size of the surface to be monitored
- Available installation space on the pipe or component
- Position of the electronics and accessibility of the connection terminals
- Routing and mechanical strain relief of the sensor cable
- Available supply voltage
- Integration of the changeover contact into the control system
- Ambient temperature and humidity exposure
- Required protection rating for the application
The direct version is particularly easy to install when the condensation monitor can be mounted directly on an accessible pipe or surface. The version with an external circuit board provides greater flexibility when positioning the sensor and electronics.
How is a condensation monitor installed correctly?
Correct installation is essential for reliable operation. With the direct version, the device is secured with the mounting strap to a bare metal pipe or a smooth, grease free surface. The mounting block must rest as fully as possible against the monitored surface and provide good thermal contact.
The mounting strap must be tightened evenly without damaging the mounting block or housing. The mounting strap supplied with the direct version is intended for pipes up to 3 inches.
With the version featuring an external circuit board, the sensor is positioned at the intended measuring point. The circuit board should be installed in a protected location that is easily accessible for the electrical connection. The sensor cable must be routed so that it is not kinked, trapped or subjected to mechanical stress.
The sensor must be sufficiently exposed to the surrounding air. Covers, insulation or other components must not restrict the necessary air exchange at the sensing element. The electrical connection must be carried out according to the connection assignment in the operating instructions.
Which factors affect reliable operation?
The reliable operation of a condensation monitor depends largely on the installation, the environment and the condition of the sensing element. The sensor should be protected from mechanical damage, excessive contamination and unsuitable ambient conditions.
The devices are intended for clean air as well as non aggressive and non combustible gases. Dust, deposits or permanently restricted air circulation can affect humidity detection. The installation location should therefore be selected so that the sensor can record the actual conditions at the monitored point.
The permissible operating temperature is -30 °C to +70 °C. The storage temperature range is -35 °C to +85 °C. The housing has IP65 protection according to EN 60529. Nevertheless, the installation location should be selected so that the sensor is not unnecessarily exposed to contamination or mechanical stress.
Which technical data is important?
The condensation monitors feature a digital humidity sensor with an integrated temperature sensor. The switching point is approximately 93 % relative humidity and is permanently set. A changeover contact is provided as the output.
The power supply is 24 V AC with a tolerance of ±20 % or 15 to 36 V DC. The electrical connection is made via screw terminals for cables with a cross section of 0.14 to 1.5 mm².
The direct version features an aluminium mounting block with a length of 62 mm, a width of 25 mm and a height of 15 mm. Installation is carried out with a mounting strap for pipes up to 3 inches.
With the version featuring an external circuit board, the sensor is connected via a cable. The separate circuit board is approximately 35 mm long and 15 mm wide and has a mounting hole with a diameter of 3 mm.
Where can I find further technical documents?
The product pages for both condensation monitors provide the complete technical data, connection information and installation instructions. A data sheet, operating instructions and declaration of conformity are also available for both versions.
| Condensation monitor | Data sheet | Operating instructions | Declaration of conformity |
| Condensation monitor with changeover contact |  | | |
| Condensation monitor with changeover contact and external circuit board | | | |
Frequently asked questions about condensation monitors
What does a condensation monitor measure?
A condensation monitor monitors relative humidity and temperature in the area of a surface at risk. When the fixed switching point of approximately 93 % relative humidity is reached, the changeover contact switches.
What is the difference between a condensation monitor and a dew point monitor?
A condensation monitor switches at a fixed relative humidity value. A dew point monitor, on the other hand, calculates the dew point from humidity and temperature and monitors the conditions in relation to the surface temperature. The appropriate solution depends on the application and the required signal processing.
When is the version with an external circuit board suitable?
The version with an external circuit board is suitable when the sensor needs to be positioned at a difficult to access or confined measuring point. The electronics can be installed independently in a suitable and easily accessible location.
Can the condensation monitor be installed on pipes?
The direct version is installed on suitable pipes using a mounting block and mounting strap. The mounting strap is intended for pipes up to 3 inches. Suitability depends on the surface and the installation situation.
What is the fixed switching point?
The switching point is approximately 93 % relative humidity and is permanently set. The switching point cannot be adjusted individually on these versions.
Which protection rating and temperature range apply?
Both versions have IP65 protection according to EN 60529. The permissible operating temperature is -30 °C to +70 °C. The storage temperature range is -35 °C to +85 °C.
